/*!
 * Vue.js v2.6.12
 * (c) 2014-2020 Evan You
 * Released under the MIT License.
 */
(function (global, factory) {
   typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
   typeof define === 'function' && define.amd ? define(factory) :
   (global = global || self, global.Vue = factory());
 }(this, function () { 'use strict';
 
   /*  */
 
   var emptyObject = Object.freeze({});
 
   // These helpers produce better VM code in JS engines due to their
   // explicitness and function inlining.
   function isUndef (v) {
     return v === undefined || v === null
   }
 
   function isDef (v) {
     return v !== undefined && v !== null
   }
 
   function isTrue (v) {
     return v === true
   }
 
   function isFalse (v) {
     return v === false
   }
 
   /**
    * Check if value is primitive.
    */
   function isPrimitive (value) {
     return (
       typeof value === 'string' ||
       typeof value === 'number' ||
       // $flow-disable-line
       typeof value === 'symbol' ||
       typeof value === 'boolean'
     )
   }
 
   /**
    * Quick object check - this is primarily used to tell
    * Objects from primitive values when we know the value
    * is a JSON-compliant type.
    */
   function isObject (obj) {
     return obj !== null && typeof obj === 'object'
   }
 
   /**
    * Get the raw type string of a value, e.g., [object Object].
    */
   var _toString = Object.prototype.toString;
 
   function toRawType (value) {
     return _toString.call(value).slice(8, -1)
   }
 
   /**
    * Strict object type check. Only returns true
    * for plain JavaScript objects.
    */
   function isPlainObject (obj) {
     return _toString.call(obj) === '[object Object]'
   }
 
   function isRegExp (v) {
     return _toString.call(v) === '[object RegExp]'
   }
 
   /**
    * Check if val is a valid array index.
    */
   function isValidArrayIndex (val) {
     var n = parseFloat(String(val));
     return n >= 0 && Math.floor(n) === n && isFinite(val)
   }
 
   function isPromise (val) {
     return (
       isDef(val) &&
       typeof val.then === 'function' &&
       typeof val.catch === 'function'
     )
   }
 
   /**
    * Convert a value to a string that is actually rendered.
    */
   function toString (val) {
     return val == null
       ? ''
       : Array.isArray(val) || (isPlainObject(val) && val.toString === _toString)
         ? JSON.stringify(val, null, 2)
         : String(val)
   }
 
   /**
    * Convert an input value to a number for persistence.
    * If the conversion fails, return original string.
    */
   function toNumber (val) {
     var n = parseFloat(val);
     return isNaN(n) ? val : n
   }
 
   /**
    * Make a map and return a function for checking if a key
    * is in that map.
    */
   function makeMap (
     str,
     expectsLowerCase
   ) {
     var map = Object.create(null);
     var list = str.split(',');
     for (var i = 0; i < list.length; i++) {
       map[list[i]] = true;
     }
     return expectsLowerCase
       ? function (val) { return map[val.toLowerCase()]; }
       : function (val) { return map[val]; }
   }
 
   /**
    * Check if a tag is a built-in tag.
    */
   var isBuiltInTag = makeMap('slot,component', true);
 
   /**
    * Check if an attribute is a reserved attribute.
    */
   var isReservedAttribute = makeMap('key,ref,slot,slot-scope,is');
 
   /**
    * Remove an item from an array.
    */
   function remove (arr, item) {
     if (arr.length) {
       var index = arr.indexOf(item);
       if (index > -1) {
         return arr.splice(index, 1)
       }
     }
   }
 
   /**
    * Check whether an object has the property.
    */
   var hasOwnProperty = Object.prototype.hasOwnProperty;
   function hasOwn (obj, key) {
     return hasOwnProperty.call(obj, key)
   }
 
   /**
    * Create a cached version of a pure function.
    */
   function cached (fn) {
     var cache = Object.create(null);
     return (function cachedFn (str) {
       var hit = cache[str];
       return hit || (cache[str] = fn(str))
     })
   }
 
   /**
    * Camelize a hyphen-delimited string.
    */
   var camelizeRE = /-(\w)/g;
   var camelize = cached(function (str) {
     return str.replace(camelizeRE, function (_, c) { return c ? c.toUpperCase() : ''; })
   });
 
   /**
    * Capitalize a string.
    */
   var capitalize = cached(function (str) {
     return str.charAt(0).toUpperCase() + str.slice(1)
   });
 
   /**
    * Hyphenate a camelCase string.
    */
   var hyphenateRE = /\B([A-Z])/g;
   var hyphenate = cached(function (str) {
     return str.replace(hyphenateRE, '-$1').toLowerCase()
   });
 
   /**
    * Simple bind polyfill for environments that do not support it,
    * e.g., PhantomJS 1.x. Technically, we don't need this anymore
    * since native bind is now performant enough in most browsers.
    * But removing it would mean breaking code that was able to run in
    * PhantomJS 1.x, so this must be kept for backward compatibility.
    */
 
   /* istanbul ignore next */
   function polyfillBind (fn, ctx) {
     function boundFn (a) {
       var l = arguments.length;
       return l
         ? l > 1
           ? fn.apply(ctx, arguments)
           : fn.call(ctx, a)
         : fn.call(ctx)
     }
 
     boundFn._length = fn.length;
     return boundFn
   }
 
   function nativeBind (fn, ctx) {
     return fn.bind(ctx)
   }
 
   var bind = Function.prototype.bind
     ? nativeBind
     : polyfillBind;
 
   /**
    * Convert an Array-like object to a real Array.
    */
   function toArray (list, start) {
     start = start || 0;
     var i = list.length - start;
     var ret = new Array(i);
     while (i--) {
       ret[i] = list[i + start];
     }
     return ret
   }
 
   /**
    * Mix properties into target object.
    */
   function extend (to, _from) {
     for (var key in _from) {
       to[key] = _from[key];
     }
     return to
   }
 
   /**
    * Merge an Array of Objects into a single Object.
    */
   function toObject (arr) {
     var res = {};
     for (var i = 0; i < arr.length; i++) {
       if (arr[i]) {
         extend(res, arr[i]);
       }
     }
     return res
   }
 
   /* eslint-disable no-unused-vars */
 
   /**
    * Perform no operation.
    * Stubbing args to make Flow happy without leaving useless transpiled code
    * with ...rest (https://flow.org/blog/2017/05/07/Strict-Function-Call-Arity/).
    */
   function noop (a, b, c) {}
 
   /**
    * Always return false.
    */
   var no = function (a, b, c) { return false; };
 
   /* eslint-enable no-unused-vars */
 
   /**
    * Return the same value.
    */
   var identity = function (_) { return _; };
 
   /**
    * Generate a string containing static keys from compiler modules.
    */
   function genStaticKeys (modules) {
     return modules.reduce(function (keys, m) {
       return keys.concat(m.staticKeys || [])
     }, []).join(',')
   }
 
   /**
    * Check if two values are loosely equal - that is,
    * if they are plain objects, do they have the same shape?
    */
   function looseEqual (a, b) {
     if (a === b) { return true }
     var isObjectA = isObject(a);
     var isObjectB = isObject(b);
     if (isObjectA && isObjectB) {
       try {
         var isArrayA = Array.isArray(a);
         var isArrayB = Array.isArray(b);
         if (isArrayA && isArrayB) {
           return a.length === b.length && a.every(function (e, i) {
             return looseEqual(e, b[i])
           })
         } else if (a instanceof Date && b instanceof Date) {
           return a.getTime() === b.getTime()
         } else if (!isArrayA && !isArrayB) {
           var keysA = Object.keys(a);
           var keysB = Object.keys(b);
           return keysA.length === keysB.length && keysA.every(function (key) {
             return looseEqual(a[key], b[key])
           })
         } else {
           /* istanbul ignore next */
           return false
         }
       } catch (e) {
         /* istanbul ignore next */
         return false
       }
     } else if (!isObjectA && !isObjectB) {
       return String(a) === String(b)
     } else {
       return false
     }
   }
 
   /**
    * Return the first index at which a loosely equal value can be
    * found in the array (if value is a plain object, the array must
    * contain an object of the same shape), or -1 if it is not present.
    */
   function looseIndexOf (arr, val) {
     for (var i = 0; i < arr.length; i++) {
       if (looseEqual(arr[i], val)) { return i }
     }
     return -1
   }
 
   /**
    * Ensure a function is called only once.
    */
   function once (fn) {
     var called = false;
     return function () {
       if (!called) {
         called = true;
         fn.apply(this, arguments);
       }
     }
   }
 
   var SSR_ATTR = 'data-server-rendered';
 
   var ASSET_TYPES = [
     'component',
     'directive',
     'filter'
   ];
 
   var LIFECYCLE_HOOKS = [
     'beforeCreate',
     'created',
     'beforeMount',
     'mounted',
     'beforeUpdate',
     'updated',
     'beforeDestroy',
     'destroyed',
     'activated',
     'deactivated',
     'errorCaptured',
     'serverPrefetch'
   ];
 
   /*  */
 
 
 
   var config = ({
     /**
      * Option merge strategies (used in core/util/options)
      */
     // $flow-disable-line
     optionMergeStrategies: Object.create(null),
 
     /**
      * Whether to suppress warnings.
      */
     silent: false,
 
     /**
      * Show production mode tip message on boot?
      */
     productionTip: "development" !== 'production',
 
     /**
      * Whether to enable devtools
      */
     devtools: "development" !== 'production',
 
     /**
      * Whether to record perf
      */
     performance: false,
 
     /**
      * Error handler for watcher errors
      */
     errorHandler: null,
 
     /**
      * Warn handler for watcher warns
      */
     warnHandler: null,
 
     /**
      * Ignore certain custom elements
      */
     ignoredElements: [],
 
     /**
      * Custom user key aliases for v-on
      */
     // $flow-disable-line
     keyCodes: Object.create(null),
 
     /**
      * Check if a tag is reserved so that it cannot be registered as a
      * component. This is platform-dependent and may be overwritten.
      */
     isReservedTag: no,
 
     /**
      * Check if an attribute is reserved so that it cannot be used as a component
      * prop. This is platform-dependent and may be overwritten.
      */
     isReservedAttr: no,
 
     /**
      * Check if a tag is an unknown element.
      * Platform-dependent.
      */
     isUnknownElement: no,
 
     /**
      * Get the namespace of an element
      */
     getTagNamespace: noop,
 
     /**
      * Parse the real tag name for the specific platform.
      */
     parsePlatformTagName: identity,
 
     /**
      * Check if an attribute must be bound using property, e.g. value
      * Platform-dependent.
      */
     mustUseProp: no,
 
     /**
      * Perform updates asynchronously. Intended to be used by Vue Test Utils
      * This will significantly reduce performance if set to false.
      */
     async: true,
 
     /**
      * Exposed for legacy reasons
      */
     _lifecycleHooks: LIFECYCLE_HOOKS
   });
 
   /*  */
 
   /**
    * unicode letters used for parsing html tags, component names and property paths.
    * using https://www.w3.org/TR/html53/semantics-scripting.html#potentialcustomelementname
    * skipping \u10000-\uEFFFF due to it freezing up PhantomJS
    */
   var unicodeRegExp = /a-zA-Z\u00B7\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u037D\u037F-\u1FFF\u200C-\u200D\u203F-\u2040\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD/;
 
   /**
    * Check if a string starts with $ or _
    */
   function isReserved (str) {
     var c = (str + '').charCodeAt(0);
     return c === 0x24 || c === 0x5F
   }
 
   /**
    * Define a property.
    */
   function def (obj, key, val, enumerable) {
     Object.defineProperty(obj, key, {
       value: val,
       enumerable: !!enumerable,
       writable: true,
       configurable: true
     });
   }
 
   /**
    * Parse simple path.
    */
   var bailRE = new RegExp(("[^" + (unicodeRegExp.source) + ".$_\\d]"));
   function parsePath (path) {
     if (bailRE.test(path)) {
       return
     }
     var segments = path.split('.');
     return function (obj) {
       for (var i = 0; i < segments.length; i++) {
         if (!obj) { return }
         obj = obj[segments[i]];
       }
       return obj
     }
   }
 
   /*  */
 
   // can we use __proto__?
   var hasProto = '__proto__' in {};
 
   // Browser environment sniffing
   var inBrowser = typeof window !== 'undefined';
   var inWeex = typeof WXEnvironment !== 'undefined' && !!WXEnvironment.platform;
   var weexPlatform = inWeex && WXEnvironment.platform.toLowerCase();
   var UA = inBrowser && window.navigator.userAgent.toLowerCase();
   var isIE = UA && /msie|trident/.test(UA);
   var isIE9 = UA && UA.indexOf('msie 9.0') > 0;
   var isEdge = UA && UA.indexOf('edge/') > 0;
   var isAndroid = (UA && UA.indexOf('android') > 0) || (weexPlatform === 'android');
   var isIOS = (UA && /iphone|ipad|ipod|ios/.test(UA)) || (weexPlatform === 'ios');
   var isChrome = UA && /chrome\/\d+/.test(UA) && !isEdge;
   var isPhantomJS = UA && /phantomjs/.test(UA);
   var isFF = UA && UA.match(/firefox\/(\d+)/);
 
   // Firefox has a "watch" function on Object.prototype...
   var nativeWatch = ({}).watch;
 
   var supportsPassive = false;
   if (inBrowser) {
     try {
       var opts = {};
       Object.defineProperty(opts, 'passive', ({
         get: function get () {
           /* istanbul ignore next */
           supportsPassive = true;
         }
       })); // https://github.com/facebook/flow/issues/285
       window.addEventListener('test-passive', null, opts);
     } catch (e) {}
   }
 
   // this needs to be lazy-evaled because vue may be required before
   // vue-server-renderer can set VUE_ENV
   var _isServer;
   var isServerRendering = function () {
     if (_isServer === undefined) {
       /* istanbul ignore if */
       if (!inBrowser && !inWeex && typeof global !== 'undefined') {
         // detect presence of vue-server-renderer and avoid
         // Webpack shimming the process
         _isServer = global['process'] && global['process'].env.VUE_ENV === 'server';
       } else {
         _isServer = false;
       }
     }
     return _isServer
   };
 
   // detect devtools
   var devtools = inBrowser && window.__VUE_DEVTOOLS_GLOBAL_HOOK__;
 
   /* istanbul ignore next */
   function isNative (Ctor) {
     return typeof Ctor === 'function' && /native code/.test(Ctor.toString())
   }
 
   var hasSymbol =
     typeof Symbol !== 'undefined' && isNative(Symbol) &&
     typeof Reflect !== 'undefined' && isNative(Reflect.ownKeys);
 
   var _Set;
   /* istanbul ignore if */ // $flow-disable-line
   if (typeof Set !== 'undefined' && isNative(Set)) {
     // use native Set when available.
     _Set = Set;
   } else {
     // a non-standard Set polyfill that only works with primitive keys.
     _Set = /*@__PURE__*/(function () {
       function Set () {
         this.set = Object.create(null);
       }
       Set.prototype.has = function has (key) {
         return this.set[key] === true
       };
       Set.prototype.add = function add (key) {
         this.set[key] = true;
       };
       Set.prototype.clear = function clear () {
         this.set = Object.create(null);
       };
 
       return Set;
     }());
   }
 
   /*  */
 
   var warn = noop;
   var tip = noop;
   var generateComponentTrace = (noop); // work around flow check
   var formatComponentName = (noop);
 
   {
     var hasConsole = typeof console !== 'undefined';
     var classifyRE = /(?:^|[-_])(\w)/g;
     var classify = function (str) { return str
       .replace(classifyRE, function (c) { return c.toUpperCase(); })
       .replace(/[-_]/g, ''); };
 
     warn = function (msg, vm) {
       var trace = vm ? generateComponentTrace(vm) : '';
 
       if (config.warnHandler) {
         config.warnHandler.call(null, msg, vm, trace);
       } else if (hasConsole && (!config.silent)) {
         console.error(("[Vue warn]: " + msg + trace));
       }
     };
 
     tip = function (msg, vm) {
       if (hasConsole && (!config.silent)) {
         console.warn("[Vue tip]: " + msg + (
           vm ? generateComponentTrace(vm) : ''
         ));
       }
     };
 
     formatComponentName = function (vm, includeFile) {
       if (vm.$root === vm) {
         return '<Root>'
       }
       var options = typeof vm === 'function' && vm.cid != null
         ? vm.options
         : vm._isVue
           ? vm.$options || vm.constructor.options
           : vm;
       var name = options.name || options._componentTag;
       var file = options.__file;
       if (!name && file) {
         var match = file.match(/([^/\\]+)\.vue$/);
         name = match && match[1];
       }
 
       return (
         (name ? ("<" + (classify(name)) + ">") : "<Anonymous>") +
         (file && includeFile !== false ? (" at " + file) : '')
       )
     };
 
     var repeat = function (str, n) {
       var res = '';
       while (n) {
         if (n % 2 === 1) { res += str; }
         if (n > 1) { str += str; }
         n >>= 1;
       }
       return res
     };
 
     generateComponentTrace = function (vm) {
       if (vm._isVue && vm.$parent) {
         var tree = [];
         var currentRecursiveSequence = 0;
         while (vm) {
           if (tree.length > 0) {
             var last = tree[tree.length - 1];
             if (last.constructor === vm.constructor) {
               currentRecursiveSequence++;
               vm = vm.$parent;
               continue
             } else if (currentRecursiveSequence > 0) {
               tree[tree.length - 1] = [last, currentRecursiveSequence];
               currentRecursiveSequence = 0;
             }
           }
           tree.push(vm);
           vm = vm.$parent;
         }
         return '\n\nfound in\n\n' + tree
           .map(function (vm, i) { return ("" + (i === 0 ? '---> ' : repeat(' ', 5 + i * 2)) + (Array.isArray(vm)
               ? ((formatComponentName(vm[0])) + "... (" + (vm[1]) + " recursive calls)")
               : formatComponentName(vm))); })
           .join('\n')
       } else {
         return ("\n\n(found in " + (formatComponentName(vm)) + ")")
       }
     };
   }
 
   /*  */
 
   var uid = 0;
 
   /**
    * A dep is an observable that can have multiple
    * directives subscribing to it.
    */
   var Dep = function Dep () {
     this.id = uid++;
     this.subs = [];
   };
 
   Dep.prototype.addSub = function addSub (sub) {
     this.subs.push(sub);
   };
 
   Dep.prototype.removeSub = function removeSub (sub) {
     remove(this.subs, sub);
   };
 
   Dep.prototype.depend = function depend () {
     if (Dep.target) {
       Dep.target.addDep(this);
     }
   };
 
   Dep.prototype.notify = function notify () {
     // stabilize the subscriber list first
     var subs = this.subs.slice();
     if (!config.async) {
       // subs aren't sorted in scheduler if not running async
       // we need to sort them now to make sure they fire in correct
       // order
       subs.sort(function (a, b) { return a.id - b.id; });
     }
     for (var i = 0, l = subs.length; i < l; i++) {
       subs[i].update();
     }
   };
 
   // The current target watcher being evaluated.
   // This is globally unique because only one watcher
   // can be evaluated at a time.
   Dep.target = null;
   var targetStack = [];
 
   function pushTarget (target) {
     targetStack.push(target);
     Dep.target = target;
   }
 
   function popTarget () {
     targetStack.pop();
     Dep.target = targetStack[targetStack.length - 1];
   }
 
   /*  */
 
   var VNode = function VNode (
     tag,
     data,
     children,
     text,
     elm,
     context,
     componentOptions,
     asyncFactory
   ) {
     this.tag = tag;
     this.data = data;
     this.children = children;
     this.text = text;
     this.elm = elm;
     this.ns = undefined;
     this.context = context;
     this.fnContext = undefined;
     this.fnOptions = undefined;
     this.fnScopeId = undefined;
     this.key = data && data.key;
     this.componentOptions = componentOptions;
     this.componentInstance = undefined;
     this.parent = undefined;
     this.raw = false;
     this.isStatic = false;
     this.isRootInsert = true;
     this.isComment = false;
     this.isCloned = false;
     this.isOnce = false;
     this.asyncFactory = asyncFactory;
     this.asyncMeta = undefined;
     this.isAsyncPlaceholder = false;
   };
 
   var prototypeAccessors = { child: { configurable: true } };
 
   // DEPRECATED: alias for componentInstance for backwards compat.
   /* istanbul ignore next */
   prototypeAccessors.child.get = function () {
     return this.componentInstance
   };
 
   Object.defineProperties( VNode.prototype, prototypeAccessors );
 
   var createEmptyVNode = function (text) {
     if ( text === void 0 ) text = '';
 
     var node = new VNode();
     node.text = text;
     node.isComment = true;
     return node
   };
 
   function createTextVNode (val) {
     return new VNode(undefined, undefined, undefined, String(val))
   }
 
   // optimized shallow clone
   // used for static nodes and slot nodes because they may be reused across
   // multiple renders, cloning them avoids errors when DOM manipulations rely
   // on their elm reference.
   function cloneVNode (vnode) {
     var cloned = new VNode(
       vnode.tag,
       vnode.data,
       // #7975
       // clone children array to avoid mutating original in case of cloning
       // a child.
       vnode.children && vnode.children.slice(),
       vnode.text,
       vnode.elm,
       vnode.context,
       vnode.componentOptions,
       vnode.asyncFactory
     );
     cloned.ns = vnode.ns;
     cloned.isStatic = vnode.isStatic;
     cloned.key = vnode.key;
     cloned.isComment = vnode.isComment;
     cloned.fnContext = vnode.fnContext;
     cloned.fnOptions = vnode.fnOptions;
     cloned.fnScopeId = vnode.fnScopeId;
     cloned.asyncMeta = vnode.asyncMeta;
     cloned.isCloned = true;
     return cloned
   }
 
   /*
    * not type checking this file because flow doesn't play well with
    * dynamically accessing methods on Array prototype
    */
 
   var arrayProto = Array.prototype;
   var arrayMethods = Object.create(arrayProto);
 
   var methodsToPatch = [
     'push',
     'pop',
     'shift',
     'unshift',
     'splice',
     'sort',
     'reverse'
   ];
 
   /**
    * Intercept mutating methods and emit events
    */
   methodsToPatch.forEach(function (method) {
     // cache original method
     var original = arrayProto[method];
     def(arrayMethods, method, function mutator () {
       var args = [], len = arguments.length;
       while ( len-- ) args[ len ] = arguments[ len ];
 
       var result = original.apply(this, args);
       var ob = this.__ob__;
       var inserted;
       switch (method) {
         case 'push':
         case 'unshift':
           inserted = args;
           break
         case 'splice':
           inserted = args.slice(2);
           break
       }
       if (inserted) { ob.observeArray(inserted); }
       // notify change
       ob.dep.notify();
       return result
     });
   });
 
   /*  */
 
   var arrayKeys = Object.getOwnPropertyNames(arrayMethods);
 
   /**
    * In some cases we may want to disable observation inside a component's
    * update computation.
    */
   var shouldObserve = true;
 
   function toggleObserving (value) {
     shouldObserve = value;
   }
 
   /**
    * Observer class that is attached to each observed
    * object. Once attached, the observer converts the target
    * object's property keys into getter/setters that
    * collect dependencies and dispatch updates.
    */
   var Observer = function Observer (value) {
     this.value = value;
     this.dep = new Dep();
     this.vmCount = 0;
     def(value, '__ob__', this);
     if (Array.isArray(value)) {
       if (hasProto) {
         protoAugment(value, arrayMethods);
       } else {
         copyAugment(value, arrayMethods, arrayKeys);
       }
       this.observeArray(value);
     } else {
       this.walk(value);
     }
   };
 
   /**
    * Walk through all properties and convert them into
    * getter/setters. This method should only be called when
    * value type is Object.
    */
   Observer.prototype.walk = function walk (obj) {
     var keys = Object.keys(obj);
     for (var i = 0; i < keys.length; i++) {
       defineReactive$$1(obj, keys[i]);
     }
   };
 
   /**
    * Observe a list of Array items.
    */
   Observer.prototype.observeArray = function observeArray (items) {
     for (var i = 0, l = items.length; i < l; i++) {
       observe(items[i]);
     }
   };
 
   // helpers
 
   /**
    * Augment a target Object or Array by intercepting
    * the prototype chain using __proto__
    */
   function protoAugment (target, src) {
     /* eslint-disable no-proto */
     target.__proto__ = src;
     /* eslint-enable no-proto */
   }
 
   /**
    * Augment a target Object or Array by defining
    * hidden properties.
    */
   /* istanbul ignore next */
   function copyAugment (target, src, keys) {
     for (var i = 0, l = keys.length; i < l; i++) {
       var key = keys[i];
       def(target, key, src[key]);
     }
   }
 
   /**
    * Attempt to create an observer instance for a value,
    * returns the new observer if successfully observed,
    * or the existing observer if the value already has one.
    */
   function observe (value, asRootData) {
     if (!isObject(value) || value instanceof VNode) {
       return
     }
     var ob;
     if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) {
       ob = value.__ob__;
     } else if (
       shouldObserve &&
       !isServerRendering() &&
       (Array.isArray(value) || isPlainObject(value)) &&
       Object.isExtensible(value) &&
       !value._isVue
     ) {
       ob = new Observer(value);
     }
     if (asRootData && ob) {
       ob.vmCount++;
     }
     return ob
   }
 
   /**
    * Define a reactive property on an Object.
    */
   function defineReactive$$1 (
     obj,
     key,
     val,
     customSetter,
     shallow
   ) {
     var dep = new Dep();
 
     var property = Object.getOwnPropertyDescriptor(obj, key);
     if (property && property.configurable === false) {
       return
     }
 
     // cater for pre-defined getter/setters
     var getter = property && property.get;
     var setter = property && property.set;
     if ((!getter || setter) && arguments.length === 2) {
       val = obj[key];
     }
 
     var childOb = !shallow && observe(val);
     Object.defineProperty(obj, key, {
       enumerable: true,
       configurable: true,
       get: function reactiveGetter () {
         var value = getter ? getter.call(obj) : val;
         if (Dep.target) {
           dep.depend();
           if (childOb) {
             childOb.dep.depend();
             if (Array.isArray(value)) {
               dependArray(value);
             }
           }
         }
         return value
       },
       set: function reactiveSetter (newVal) {
         var value = getter ? getter.call(obj) : val;
         /* eslint-disable no-self-compare */
         if (newVal === value || (newVal !== newVal && value !== value)) {
           return
         }
         /* eslint-enable no-self-compare */
         if (customSetter) {
           customSetter();
         }
         // #7981: for accessor properties without setter
         if (getter && !setter) { return }
         if (setter) {
           setter.call(obj, newVal);
         } else {
           val = newVal;
         }
         childOb = !shallow && observe(newVal);
         dep.notify();
       }
     });
   }
 
   /**
    * Set a property on an object. Adds the new property and
    * triggers change notification if the property doesn't
    * already exist.
    */
   function set (target, key, val) {
     if (isUndef(target) || isPrimitive(target)
     ) {
       warn(("Cannot set reactive property on undefined, null, or primitive value: " + ((target))));
     }
     if (Array.isArray(target) && isValidArrayIndex(key)) {
       target.length = Math.max(target.length, key);
       target.splice(key, 1, val);
       return val
     }
     if (key in target && !(key in Object.prototype)) {
       target[key] = val;
       return val
     }
     var ob = (target).__ob__;
     if (target._isVue || (ob && ob.vmCount)) {
       warn(
         'Avoid adding reactive properties to a Vue instance or its root $data ' +
         'at runtime - declare it upfront in the data option.'
       );
       return val
     }
     if (!ob) {
       target[key] = val;
       return val
     }
     defineReactive$$1(ob.value, key, val);
     ob.dep.notify();
     return val
   }
 
   /**
    * Delete a property and trigger change if necessary.
    */
   function del (target, key) {
     if (isUndef(target) || isPrimitive(target)
     ) {
       warn(("Cannot delete reactive property on undefined, null, or primitive value: " + ((target))));
     }
     if (Array.isArray(target) && isValidArrayIndex(key)) {
       target.splice(key, 1);
       return
     }
     var ob = (target).__ob__;
     if (target._isVue || (ob && ob.vmCount)) {
       warn(
         'Avoid deleting properties on a Vue instance or its root $data ' +
         '- just set it to null.'
       );
       return
     }
     if (!hasOwn(target, key)) {
       return
     }
     delete target[key];
     if (!ob) {
       return
     }
     ob.dep.notify();
   }
 
   /**
    * Collect dependencies on array elements when the array is touched, since
    * we cannot intercept array element access like property getters.
    */
   function dependArray (value) {
     for (var e = (void 0), i = 0, l = value.length; i < l; i++) {
       e = value[i];
       e && e.__ob__ && e.__ob__.dep.depend();
       if (Array.isArray(e)) {
         dependArray(e);
       }
     }
   }
 
   /*  */
 
   /**
    * Option overwriting strategies are functions that handle
    * how to merge a parent option value and a child option
    * value into the final value.
    */
   var strats = config.optionMergeStrategies;
 
   /**
    * Options with restrictions
    */
   {
     strats.el = strats.propsData = function (parent, child, vm, key) {
       if (!vm) {
         warn(
           "option \"" + key + "\" can only be used during instance " +
           'creation with the `new` keyword.'
         );
       }
       return defaultStrat(parent, child)
     };
   }
 
   /**
    * Helper that recursively merges two data objects together.
    */
   function mergeData (to, from) {
     if (!from) { return to }
     var key, toVal, fromVal;
 
     var keys = hasSymbol
       ? Reflect.ownKeys(from)
       : Object.keys(from);
 
     for (var i = 0; i < keys.length; i++) {
       key = keys[i];
       // in case the object is already observed...
       if (key === '__ob__') { continue }
       toVal = to[key];
       fromVal = from[key];
       if (!hasOwn(to, key)) {
         set(to, key, fromVal);
       } else if (
         toVal !== fromVal &&
         isPlainObject(toVal) &&
         isPlainObject(fromVal)
       ) {
         mergeData(toVal, fromVal);
       }
     }
     return to
   }
 
   /**
    * Data
    */
   function mergeDataOrFn (
     parentVal,
     childVal,
     vm
   ) {
     if (!vm) {
       // in a Vue.extend merge, both should be functions
       if (!childVal) {
         return parentVal
       }
       if (!parentVal) {
         return childVal
       }
       // when parentVal & childVal are both present,
       // we need to return a function that returns the
       // merged result of both functions... no need to
       // check if parentVal is a function here because
       // it has to be a function to pass previous merges.
       return function mergedDataFn () {
         return mergeData(
           typeof childVal === 'function' ? childVal.call(this, this) : childVal,
           typeof parentVal === 'function' ? parentVal.call(this, this) : parentVal
         )
       }
     } else {
       return function mergedInstanceDataFn () {
         // instance merge
         var instanceData = typeof childVal === 'function'
           ? childVal.call(vm, vm)
           : childVal;
         var defaultData = typeof parentVal === 'function'
           ? parentVal.call(vm, vm)
           : parentVal;
         if (instanceData) {
           return mergeData(instanceData, defaultData)
         } else {
           return defaultData
         }
       }
     }
   }
 
   strats.data = function (
     parentVal,
     childVal,
     vm
   ) {
     if (!vm) {
       if (childVal && typeof childVal !== 'function') {
         warn(
           'The "data" option should be a function ' +
           'that returns a per-instance value in component ' +
           'definitions.',
           vm
         );
 
         return parentVal
       }
       return mergeDataOrFn(parentVal, childVal)
     }
 
     return mergeDataOrFn(parentVal, childVal, vm)
   };
 
   /**
    * Hooks and props are merged as arrays.
    */
   function mergeHook (
     parentVal,
     childVal
   ) {
     var res = childVal
       ? parentVal
         ? parentVal.concat(childVal)
         : Array.isArray(childVal)
           ? childVal
           : [childVal]
       : parentVal;
     return res
       ? dedupeHooks(res)
       : res
   }
 
   function dedupeHooks (hooks) {
     var res = [];
     for (var i = 0; i < hooks.length; i++) {
       if (res.indexOf(hooks[i]) === -1) {
         res.push(hooks[i]);
       }
     }
     return res
   }
 
   LIFECYCLE_HOOKS.forEach(function (hook) {
     strats[hook] = mergeHook;
   });
 
   /**
    * Assets
    *
    * When a vm is present (instance creation), we need to do
    * a three-way merge between constructor options, instance
    * options and parent options.
    */
   function mergeAssets (
     parentVal,
     childVal,
     vm,
     key
   ) {
     var res = Object.create(parentVal || null);
     if (childVal) {
       assertObjectType(key, childVal, vm);
       return extend(res, childVal)
     } else {
       return res
     }
   }
 
   ASSET_TYPES.forEach(function (type) {
     strats[type + 's'] = mergeAssets;
   });
 
   /**
    * Watchers.
    *
    * Watchers hashes should not overwrite one
    * another, so we merge them as arrays.
    */
   strats.watch = function (
     parentVal,
     childVal,
     vm,
     key
   ) {
     // work around Firefox's Object.prototype.watch...
     if (parentVal === nativeWatch) { parentVal = undefined; }
     if (childVal === nativeWatch) { childVal = undefined; }
     /* istanbul ignore if */
     if (!childVal) { return Object.create(parentVal || null) }
     {
       assertObjectType(key, childVal, vm);
     }
     if (!parentVal) { return childVal }
     var ret = {};
     extend(ret, parentVal);
     for (var key$1 in childVal) {
       var parent = ret[key$1];
       var child = childVal[key$1];
       if (parent && !Array.isArray(parent)) {
         parent = [parent];
       }
       ret[key$1] = parent
         ? parent.concat(child)
         : Array.isArray(child) ? child : [child];
     }
     return ret
   };
 
   /**
    * Other object hashes.
    */
   strats.props =
   strats.methods =
   strats.inject =
   strats.computed = function (
     parentVal,
     childVal,
     vm,
     key
   ) {
     if (childVal && "development" !== 'production') {
       assertObjectType(key, childVal, vm);
     }
     if (!parentVal) { return childVal }
     var ret = Object.create(null);
     extend(ret, parentVal);
     if (childVal) { extend(ret, childVal); }
     return ret
   };
   strats.provide = mergeDataOrFn;
 
   /**
    * Default strategy.
    */
   var defaultStrat = function (parentVal, childVal) {
     return childVal === undefined
       ? parentVal
       : childVal
   };
 
   /**
    * Validate component names
    */
   function checkComponents (options) {
     for (var key in options.components) {
       validateComponentName(key);
     }
   }
 
   function validateComponentName (name) {
     if (!new RegExp(("^[a-zA-Z][\\-\\.0-9_" + (unicodeRegExp.source) + "]*$")).test(name)) {
       warn(
         'Invalid component name: "' + name + '". Component names ' +
         'should conform to valid custom element name in html5 specification.'
       );
     }
     if (isBuiltInTag(name) || config.isReservedTag(name)) {
       warn(
         'Do not use built-in or reserved HTML elements as component ' +
         'id: ' + name
       );
     }
   }
 
   /**
    * Ensure all props option syntax are normalized into the
    * Object-based format.
    */
   function normalizeProps (options, vm) {
     var props = options.props;
     if (!props) { return }
     var res = {};
     var i, val, name;
     if (Array.isArray(props)) {
       i = props.length;
       while (i--) {
         val = props[i];
         if (typeof val === 'string') {
           name = camelize(val);
           res[name] = { type: null };
         } else {
           warn('props must be strings when using array syntax.');
         }
       }
     } else if (isPlainObject(props)) {
       for (var key in props) {
         val = props[key];
         name = camelize(key);
         res[name] = isPlainObject(val)
           ? val
           : { type: val };
       }
     } else {
       warn(
         "Invalid value for option \"props\": expected an Array or an Object, " +
         "but got " + (toRawType(props)) + ".",
         vm
       );
     }
     options.props = res;
   }
 
   /**
    * Normalize all injections into Object-based format
    */
   function normalizeInject (options, vm) {
     var inject = options.inject;
     if (!inject) { return }
     var normalized = options.inject = {};
     if (Array.isArray(inject)) {
       for (var i = 0; i < inject.length; i++) {
         normalized[inject[i]] = { from: inject[i] };
       }
     } else if (isPlainObject(inject)) {
       for (var key in inject) {
         var val = inject[key];
         normalized[key] = isPlainObject(val)
           ? extend({ from: key }, val)
           : { from: val };
       }
     } else {
       warn(
         "Invalid value for option \"inject\": expected an Array or an Object, " +
         "but got " + (toRawType(inject)) + ".",
         vm
       );
     }
   }
 
   /**
    * Normalize raw function directives into object format.
    */
   function normalizeDirectives (options) {
     var dirs = options.directives;
     if (dirs) {
       for (var key in dirs) {
         var def$$1 = dirs[key];
         if (typeof def$$1 === 'function') {
           dirs[key] = { bind: def$$1, update: def$$1 };
         }
       }
     }
   }
 
   function assertObjectType (name, value, vm) {
     if (!isPlainObject(value)) {
       warn(
         "Invalid value for option \"" + name + "\": expected an Object, " +
         "but got " + (toRawType(value)) + ".",
         vm
       );
     }
   }
 
   /**
    * Merge two option objects into a new one.
    * Core utility used in both instantiation and inheritance.
    */
   function mergeOptions (
     parent,
     child,
     vm
   ) {
     {
       checkComponents(child);
     }
 
     if (typeof child === 'function') {
       child = child.options;
     }
 
     normalizeProps(child, vm);
     normalizeInject(child, vm);
     normalizeDirectives(child);
 
     // Apply extends and mixins on the child options,
     // but only if it is a raw options object that isn't
     // the result of another mergeOptions call.
     // Only merged options has the _base property.
     if (!child._base) {
       if (child.extends) {
         parent = mergeOptions(parent, child.extends, vm);
       }
       if (child.mixins) {
         for (var i = 0, l = child.mixins.length; i < l; i++) {
           parent = mergeOptions(parent, child.mixins[i], vm);
         }
       }
     }
 
     var options = {};
     var key;
     for (key in parent) {
       mergeField(key);
     }
     for (key in child) {
       if (!hasOwn(parent, key)) {
         mergeField(key);
       }
     }
     function mergeField (key) {
       var strat = strats[key] || defaultStrat;
       options[key] = strat(parent[key], child[key], vm, key);
     }
     return options
   }
 
   /**
    * Resolve an asset.
    * This function is used because child instances need access
    * to assets defined in its ancestor chain.
    */
   function resolveAsset (
     options,
     type,
     id,
     warnMissing
   ) {
     /* istanbul ignore if */
     if (typeof id !== 'string') {
       return
     }
     var assets = options[type];
     // check local registration variations first
     if (hasOwn(assets, id)) { return assets[id] }
     var camelizedId = camelize(id);
     if (hasOwn(assets, camelizedId)) { return assets[camelizedId] }
     var PascalCaseId = capitalize(camelizedId);
     if (hasOwn(assets, PascalCaseId)) { return assets[PascalCaseId] }
     // fallback to prototype chain
     var res = assets[id] || assets[camelizedId] || assets[PascalCaseId];
     if (warnMissing && !res) {
       warn(
         'Failed to resolve ' + type.slice(0, -1) + ': ' + id,
         options
       );
     }
     return res
   }
 
   /*  */
 
 
 
   function validateProp (
     key,
     propOptions,
     propsData,
     vm
   ) {
     var prop = propOptions[key];
     var absent = !hasOwn(propsData, key);
     var value = propsData[key];
     // boolean casting
     var booleanIndex = getTypeIndex(Boolean, prop.type);
     if (booleanIndex > -1) {
       if (absent && !hasOwn(prop, 'default')) {
         value = false;
       } else if (value === '' || value === hyphenate(key)) {
         // only cast empty string / same name to boolean if
         // boolean has higher priority
         var stringIndex = getTypeIndex(String, prop.type);
         if (stringIndex < 0 || booleanIndex < stringIndex) {
           value = true;
         }
       }
     }
     // check default value
     if (value === undefined) {
       value = getPropDefaultValue(vm, prop, key);
       // since the default value is a fresh copy,
       // make sure to observe it.
       var prevShouldObserve = shouldObserve;
       toggleObserving(true);
       observe(value);
       toggleObserving(prevShouldObserve);
     }
     {
       assertProp(prop, key, value, vm, absent);
     }
     return value
   }
 
   /**
    * Get the default value of a prop.
    */
   function getPropDefaultValue (vm, prop, key) {
     // no default, return undefined
     if (!hasOwn(prop, 'default')) {
       return undefined
     }
     var def = prop.default;
     // warn against non-factory defaults for Object & Array
     if (isObject(def)) {
       warn(
         'Invalid default value for prop "' + key + '": ' +
         'Props with type Object/Array must use a factory function ' +
         'to return the default value.',
         vm
       );
     }
     // the raw prop value was also undefined from previous render,
     // return previous default value to avoid unnecessary watcher trigger
     if (vm && vm.$options.propsData &&
       vm.$options.propsData[key] === undefined &&
       vm._props[key] !== undefined
     ) {
       return vm._props[key]
     }
     // call factory function for non-Function types
     // a value is Function if its prototype is function even across different execution context
     return typeof def === 'function' && getType(prop.type) !== 'Function'
       ? def.call(vm)
       : def
   }
 
   /**
    * Assert whether a prop is valid.
    */
   function assertProp (
     prop,
     name,
     value,
     vm,
     absent
   ) {
     if (prop.required && absent) {
       warn(
         'Missing required prop: "' + name + '"',
         vm
       );
       return
     }
     if (value == null && !prop.required) {
       return
     }
     var type = prop.type;
     var valid = !type || type === true;
     var expectedTypes = [];
     if (type) {
       if (!Array.isArray(type)) {
         type = [type];
       }
       for (var i = 0; i < type.length && !valid; i++) {
         var assertedType = assertType(value, type[i]);
         expectedTypes.push(assertedType.expectedType || '');
         valid = assertedType.valid;
       }
     }
 
     if (!valid) {
       warn(
         getInvalidTypeMessage(name, value, expectedTypes),
         vm
       );
       return
     }
     var validator = prop.validator;
     if (validator) {
       if (!validator(value)) {
         warn(
           'Invalid prop: custom validator check failed for prop "' + name + '".',
           vm
         );
       }
     }
   }
 
   var simpleCheckRE = /^(String|Number|Boolean|Function|Symbol)$/;
 
   function assertType (value, type) {
     var valid;
     var expectedType = getType(type);
     if (simpleCheckRE.test(expectedType)) {
       var t = typeof value;
       valid = t === expectedType.toLowerCase();
       // for primitive wrapper objects
       if (!valid && t === 'object') {
         valid = value instanceof type;
       }
     } else if (expectedType === 'Object') {
       valid = isPlainObject(value);
     } else if (expectedType === 'Array') {
       valid = Array.isArray(value);
     } else {
       valid = value instanceof type;
     }
     return {
       valid: valid,
       expectedType: expectedType
     }
   }
 
   /**
    * Use function string name to check built-in types,
    * because a simple equality check will fail when running
    * across different vms / iframes.
    */
   function getType (fn) {
     var match = fn && fn.toString().match(/^\s*function (\w+)/);
     return match ? match[1] : ''
   }
 
   function isSameType (a, b) {
     return getType(a) === getType(b)
   }
 
   function getTypeIndex (type, expectedTypes) {
     if (!Array.isArray(expectedTypes)) {
       return isSameType(expectedTypes, type) ? 0 : -1
     }
     for (var i = 0, len = expectedTypes.length; i < len; i++) {
       if (isSameType(expectedTypes[i], type)) {
         return i
       }
     }
     return -1
   }
 
   function getInvalidTypeMessage (name, value, expectedTypes) {
     var message = "Invalid prop: type check failed for prop \"" + name + "\"." +
       " Expected " + (expectedTypes.map(capitalize).join(', '));
     var expectedType = expectedTypes[0];
     var receivedType = toRawType(value);
     var expectedValue = styleValue(value, expectedType);
     var receivedValue = styleValue(value, receivedType);
     // check if we need to specify expected value
     if (expectedTypes.length === 1 &&
         isExplicable(expectedType) &&
         !isBoolean(expectedType, receivedType)) {
       message += " with value " + expectedValue;
     }
     message += ", got " + receivedType + " ";
     // check if we need to specify received value
     if (isExplicable(receivedType)) {
       message += "with value " + receivedValue + ".";
     }
     return message
   }
 
   function styleValue (value, type) {
     if (type === 'String') {
       return ("\"" + value + "\"")
     } else if (type === 'Number') {
       return ("" + (Number(value)))
     } else {
       return ("" + value)
     }
   }
 
   function isExplicable (value) {
     var explicitTypes = ['string', 'number', 'boolean'];
     return explicitTypes.some(function (elem) { return value.toLowerCase() === elem; })
   }
 
   function isBoolean () {
     var args = [], len = arguments.length;
     while ( len-- ) args[ len ] = arguments[ len ];
 
     return args.some(function (elem) { return elem.toLowerCase() === 'boolean'; })
   }
 
   /*  */
 
   function handleError (err, vm, info) {
     // Deactivate deps tracking while processing error handler to avoid possible infinite rendering.
     // See: https://github.com/vuejs/vuex/issues/1505
     pushTarget();
     try {
       if (vm) {
         var cur = vm;
         while ((cur = cur.$parent)) {
           var hooks = cur.$options.errorCaptured;
           if (hooks) {
             for (var i = 0; i < hooks.length; i++) {
               try {
                 var capture = hooks[i].call(cur, err, vm, info) === false;
                 if (capture) { return }
               } catch (e) {
                 globalHandleError(e, cur, 'errorCaptured hook');
               }
             }
           }
         }
       }
       globalHandleError(err, vm, info);
     } finally {
       popTarget();
     }
   }
 
   function invokeWithErrorHandling (
     handler,
     context,
     args,
     vm,
     info
   ) {
     var res;
     try {
       res = args ? handler.apply(context, args) : handler.call(context);
       if (res && !res._isVue && isPromise(res) && !res._handled) {
         res.catch(function (e) { return handleError(e, vm, info + " (Promise/async)"); });
         // issue #9511
         // avoid catch triggering multiple times when nested calls
         res._handled = true;
       }
     } catch (e) {
       handleError(e, vm, info);
     }
     return res
   }
 
   function globalHandleError (err, vm, info) {
     if (config.errorHandler) {
       try {
         return config.errorHandler.call(null, err, vm, info)
       } catch (e) {
         // if the user intentionally throws the original error in the handler,
         // do not log it twice
         if (e !== err) {
           logError(e, null, 'config.errorHandler');
         }
       }
     }
     logError(err, vm, info);
   }
 
   function logError (err, vm, info) {
     {
       warn(("Error in " + info + ": \"" + (err.toString()) + "\""), vm);
     }
     /* istanbul ignore else */
     if ((inBrowser || inWeex) && typeof console !== 'undefined') {
       console.error(err);
     } else {
       throw err
     }
   }
 
   /*  */
 
   var isUsingMicroTask = false;
 
   var callbacks = [];
   var pending = false;
 
   function flushCallbacks () {
     pending = false;
     var copies = callbacks.slice(0);
     callbacks.length = 0;
     for (var i = 0; i < copies.length; i++) {
       copies[i]();
     }
   }
 
   // Here we have async deferring wrappers using microtasks.
   // In 2.5 we used (macro) tasks (in combination with microtasks).
   // However, it has subtle problems when state is changed right before repaint
   // (e.g. #6813, out-in transitions).
   // Also, using (macro) tasks in event handler would cause some weird behaviors
   // that cannot be circumvented (e.g. #7109, #7153, #7546, #7834, #8109).
   // So we now use microtasks everywhere, again.
   // A major drawback of this tradeoff is that there are some scenarios
   // where microtasks have too high a priority and fire in between supposedly
   // sequential events (e.g. #4521, #6690, which have workarounds)
   // or even between bubbling of the same event (#6566).
   var timerFunc;
 
   // The nextTick behavior leverages the microtask queue, which can be accessed
   // via either native Promise.then or MutationObserver.
   // MutationObserver has wider support, however it is seriously bugged in
   // UIWebView in iOS >= 9.3.3 when triggered in touch event handlers. It
   // completely stops working after triggering a few times... so, if native
   // Promise is available, we will use it:
   /* istanbul ignore next, $flow-disable-line */
   if (typeof Promise !== 'undefined' && isNative(Promise)) {
     var p = Promise.resolve();
     timerFunc = function () {
       p.then(flushCallbacks);
       // In problematic UIWebViews, Promise.then doesn't completely break, but
       // it can get stuck in a weird state where callbacks are pushed into the
       // microtask queue but the queue isn't being flushed, until the browser
       // needs to do some other work, e.g. handle a timer. Therefore we can
       // "force" the microtask queue to be flushed by adding an empty timer.
       if (isIOS) { setTimeout(noop); }
     };
     isUsingMicroTask = true;
   } else if (!isIE && typeof MutationObserver !== 'undefined' && (
     isNative(MutationObserver) ||
     // PhantomJS and iOS 7.x
     MutationObserver.toString() === '[object MutationObserverConstructor]'
   )) {
     // Use MutationObserver where native Promise is not available,
     // e.g. PhantomJS, iOS7, Android 4.4
     // (#6466 MutationObserver is unreliable in IE11)
     var counter = 1;
     var observer = new MutationObserver(flushCallbacks);
     var textNode = document.createTextNode(String(counter));
     observer.observe(textNode, {
       characterData: true
     });
     timerFunc = function () {
       counter = (counter + 1) % 2;
       textNode.data = String(counter);
     };
     isUsingMicroTask = true;
   } else if (typeof setImmediate !== 'undefined' && isNative(setImmediate)) {
     // Fallback to setImmediate.
     // Technically it leverages the (macro) task queue,
     // but it is still a better choice than setTimeout.
     timerFunc = function () {
       setImmediate(flushCallbacks);
     };
   } else {
     // Fallback to setTimeout.
     timerFunc = function () {
       setTimeout(flushCallbacks, 0);
     };
   }
 
   function nextTick (cb, ctx) {
     var _resolve;
     callbacks.push(function () {
       if (cb) {
         try {
           cb.call(ctx);
         } catch (e) {
           handleError(e, ctx, 'nextTick');
         }
       } else if (_resolve) {
         _resolve(ctx);
       }
     });
     if (!pending) {
       pending = true;
       timerFunc();
     }
     // $flow-disable-line
     if (!cb && typeof Promise !== 'undefined') {
       return new Promise(function (resolve) {
         _resolve = resolve;
       })
     }
   }
 
   /*  */
 
   var mark;
   var measure;
 
   {
     var perf = inBrowser && window.performance;
     /* istanbul ignore if */
     if (
       perf &&
       perf.mark &&
       perf.measure &&
       perf.clearMarks &&
       perf.clearMeasures
     ) {
       mark = function (tag) { return perf.mark(tag); };
       measure = function (name, startTag, endTag) {
         perf.measure(name, startTag, endTag);
         perf.clearMarks(startTag);
         perf.clearMarks(endTag);
         // perf.clearMeasures(name)
       };
     }
   }
 
   /* not type checking this file because flow doesn't play well with Proxy */
 
   var initProxy;
 
   {
     var allowedGlobals = makeMap(
       'Infinity,undefined,NaN,isFinite,isNaN,' +
       'parseFloat,parseInt,decodeURI,decodeURIComponent,encodeURI,encodeURIComponent,' +
       'Math,Number,Date,Array,Object,Boolean,String,RegExp,Map,Set,JSON,Intl,' +
       'require' // for Webpack/Browserify
     );
 
     var warnNonPresent = function (target, key) {
       warn(
         "Property or method \"" + key + "\" is not defined on the instance but " +
         'referenced during render. Make sure that this property is reactive, ' +
         'either in the data option, or for class-based components, by ' +
         'initializing the property. ' +
         'See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.',
         target
       );
     };
 
     var warnReservedPrefix = function (target, key) {
       warn(
         "Property \"" + key + "\" must be accessed with \"$data." + key + "\" because " +
         'properties starting with "$" or "_" are not proxied in the Vue instance to ' +
         'prevent conflicts with Vue internals. ' +
         'See: https://vuejs.org/v2/api/#data',
         target
       );
     };
 
     var hasProxy =
       typeof Proxy !== 'undefined' && isNative(Proxy);
 
     if (hasProxy) {
       var isBuiltInModifier = makeMap('stop,prevent,self,ctrl,shift,alt,meta,exact');
       config.keyCodes = new Proxy(config.keyCodes, {
         set: function set (target, key, value) {
           if (isBuiltInModifier(key)) {
             warn(("Avoid overwriting built-in modifier in config.keyCodes: ." + key));
             return false
           } else {
             target[key] = value;
             return true
           }
         }
       });
     }
 
     var hasHandler = {
       has: function has (target, key) {
         var has = key in target;
         var isAllowed = allowedGlobals(key) ||
           (typeof key === 'string' && key.charAt(0) === '_' && !(key in target.$data));
         if (!has && !isAllowed) {
           if (key in target.$data) { warnReservedPrefix(target, key); }
           else { warnNonPresent(target, key); }
         }
         return has || !isAllowed
       }
     };
 
     var getHandler = {
       get: function get (target, key) {
         if (typeof key === 'string' && !(key in target)) {
           if (key in target.$data) { warnReservedPrefix(target, key); }
           else { warnNonPresent(target, key); }
         }
         return target[key]
       }
     };
 
     initProxy = function initProxy (vm) {
       if (hasProxy) {
         // determine which proxy handler to use
         var options = vm.$options;
         var handlers = options.render && options.render._withStripped
           ? getHandler
           : hasHandler;
         vm._renderProxy = new Proxy(vm, handlers);
       } else {
         vm._renderProxy = vm;
       }
     };
   }
 
   /*  */
 
   var seenObjects = new _Set();
 
   /**
    * Recursively traverse an object to evoke all converted
    * getters, so that every nested property inside the object
    * is collected as a "deep" dependency.
    */
   function traverse (val) {
     _traverse(val, seenObjects);
     seenObjects.clear();
   }
 
   function _traverse (val, seen) {
     var i, keys;
     var isA = Array.isArray(val);
     if ((!isA && !isObject(val)) || Object.isFrozen(val) || val instanceof VNode) {
       return
     }
     if (val.__ob__) {
       var depId = val.__ob__.dep.id;
       if (seen.has(depId)) {
         return
       }
       seen.add(depId);
     }
     if (isA) {
       i = val.length;
       while (i--) { _traverse(val[i], seen); }
     } else {
       keys = Object.keys(val);
       i = keys.length;
       while (i--) { _traverse(val[keys[i]], seen); }
     }
   }
 
   /*  */
 
   var normalizeEvent = cached(function (name) {
     var passive = name.charAt(0) === '&';
     name = passive ? name.slice(1) : name;
     var once$$1 = name.charAt(0) === '~'; // Prefixed last, checked first
     name = once$$1 ? name.slice(1) : name;
     var capture = name.charAt(0) === '!';
     name = capture ? name.slice(1) : name;
     return {
       name: name,
       once: once$$1,
       capture: capture,
       passive: passive
     }
   });
 
   function createFnInvoker (fns, vm) {
     function invoker () {
       var arguments$1 = arguments;
 
       var fns = invoker.fns;
       if (Array.isArray(fns)) {
         var cloned = fns.slice();
         for (var i = 0; i < cloned.length; i++) {
           invokeWithErrorHandling(cloned[i], null, arguments$1, vm, "v-on handler");
         }
       } else {
         // return handler return value for single handlers
         return invokeWithErrorHandling(fns, null, arguments, vm, "v-on handler")
       }
     }
     invoker.fns = fns;
     return invoker
   }
 
   function updateListeners (
     on,
     oldOn,
     add,
     remove$$1,
     createOnceHandler,
     vm
   ) {
     var name, def$$1, cur, old, event;
     for (name in on) {
       def$$1 = cur = on[name];
       old = oldOn[name];
       event = normalizeEvent(name);
       if (isUndef(cur)) {
         warn(
           "Invalid handler for event \"" + (event.name) + "\": got " + String(cur),
           vm
         );
       } else if (isUndef(old)) {
         if (isUndef(cur.fns)) {
           cur = on[name] = createFnInvoker(cur, vm);
         }
         if (isTrue(event.once)) {
           cur = on[name] = createOnceHandler(event.name, cur, event.capture);
         }
         add(event.name, cur, event.capture, event.passive, event.params);
       } else if (cur !== old) {
         old.fns = cur;
         on[name] = old;
       }
     }
     for (name in oldOn) {
       if (isUndef(on[name])) {
         event = normalizeEvent(name);
         remove$$1(event.name, oldOn[name], event.capture);
       }
     }
   }
 
   /*  */
 
   function mergeVNodeHook (def, hookKey, hook) {
     if (def instanceof VNode) {
       def = def.data.hook || (def.data.hook = {});
     }
     var invoker;
     var oldHook = def[hookKey];
 
     function wrappedHook () {
       hook.apply(this, arguments);
       // important: remove merged hook to ensure it's called only once
       // and prevent memory leak
       remove(invoker.fns, wrappedHook);
     }
 
     if (isUndef(oldHook)) {
       // no existing hook
       invoker = createFnInvoker([wrappedHook]);
     } else {
       /* istanbul ignore if */
       if (isDef(oldHook.fns) && isTrue(oldHook.merged)) {
         // already a merged invoker
         invoker = oldHook;
         invoker.fns.push(wrappedHook);
       } else {
         // existing plain hook
         invoker = createFnInvoker([oldHook, wrappedHook]);
       }
     }
 
     invoker.merged = true;
     def[hookKey] = invoker;
   }
 
   /*  */
 
   function extractPropsFromVNodeData (
     data,
     Ctor,
     tag
   ) {
     // we are only extracting raw values here.
     // validation and default values are handled in the child
     // component itself.
     var propOptions = Ctor.options.props;
     if (isUndef(propOptions)) {
       return
     }
     var res = {};
     var attrs = data.attrs;
     var props = data.props;
     if (isDef(attrs) || isDef(props)) {
       for (var key in propOptions) {
         var altKey = hyphenate(key);
         {
           var keyInLowerCase = key.toLowerCase();
           if (
             key !== keyInLowerCase &&
             attrs && hasOwn(attrs, keyInLowerCase)
           ) {
             tip(
               "Prop \"" + keyInLowerCase + "\" is passed to component " +
               (formatComponentName(tag || Ctor)) + ", but the declared prop name is" +
               " \"" + key + "\". " +
               "Note that HTML attributes are case-insensitive and camelCased " +
               "props need to use their kebab-case equivalents when using in-DOM " +
               "templates. You should probably use \"" + altKey + "\" instead of \"" + key + "\"."
             );
           }
         }
         checkProp(res, props, key, altKey, true) ||
         checkProp(res, attrs, key, altKey, false);
       }
     }
     return res
   }
 
   function checkProp (
     res,
     hash,
     key,
     altKey,
     preserve
   ) {
     if (isDef(hash)) {
       if (hasOwn(hash, key)) {
         res[key] = hash[key];
         if (!preserve) {
           delete hash[key];
         }
         return true
       } else if (hasOwn(hash, altKey)) {
         res[key] = hash[altKey];
         if (!preserve) {
           delete hash[altKey];
         }
         return true
       }
     }
     return false
   }
 
   /*  */
 
   // The template compiler attempts to minimize the need for normalization by
   // statically analyzing the template at compile time.
   //
   // For plain HTML markup, normalization can be completely skipped because the
   // generated render function is guaranteed to return Array<VNode>. There are
   // two cases where extra normalization is needed:
 
   // 1. When the children contains components - because a functional component
   // may return an Array instead of a single root. In this case, just a simple
   // normalization is needed - if any child is an Array, we flatten the whole
   // thing with Array.prototype.concat. It is guaranteed to be only 1-level deep
   // because functional components already normalize their own children.
   function simpleNormalizeChildren (children) {
     for (var i = 0; i < children.length; i++) {
       if (Array.isArray(children[i])) {
         return Array.prototype.concat.apply([], children)
       }
     }
     return children
   }
 
   // 2. When the children contains constructs that always generated nested Arrays,
   // e.g. <template>, <slot>, v-for, or when the children is provided by user
   // with hand-written render functions / JSX. In such cases a full normalization
   // is needed to cater to all possible types of children values.
   function normalizeChildren (children) {
     return isPrimitive(children)
       ? [createTextVNode(children)]
       : Array.isArray(children)
         ? normalizeArrayChildren(children)
         : undefined
   }
 
   function isTextNode (node) {
     return isDef(node) && isDef(node.text) && isFalse(node.isComment)
   }
 
   function normalizeArrayChildren (children, nestedIndex) {
     var res = [];
     var i, c, lastIndex, last;
     for (i = 0; i < children.length; i++) {
       c = children[i];
       if (isUndef(c) || typeof c === 'boolean') { continue }
       lastIndex = res.length - 1;
       last = res[lastIndex];
       //  nested
       if (Array.isArray(c)) {
         if (c.length > 0) {
           c = normalizeArrayChildren(c, ((nestedIndex || '') + "_" + i));
           // merge adjacent text nodes
           if (isTextNode(c[0]) && isTextNode(last)) {
             res[lastIndex] = createTextVNode(last.text + (c[0]).text);
             c.shift();
           }
           res.push.apply(res, c);
         }
       } else if (isPrimitive(c)) {
         if (isTextNode(last)) {
           // merge adjacent text nodes
           // this is necessary for SSR hydration because text nodes are
           // essentially merged when rendered to HTML strings
           res[lastIndex] = createTextVNode(last.text + c);
         } else if (c !== '') {
           // convert primitive to vnode
           res.push(createTextVNode(c));
         }
       } else {
         if (isTextNode(c) && isTextNode(last)) {
           // merge adjacent text nodes
           res[lastIndex] = createTextVNode(last.text + c.text);
         } else {
           // default key for nested array children (likely generated by v-for)
           if (isTrue(children._isVList) &&
             isDef(c.tag) &&
             isUndef(c.key) &&
             isDef(nestedIndex)) {
             c.key = "__vlist" + nestedIndex + "_" + i + "__";
           }
           res.push(c);
         }
       }
     }
     return res
   }
 
   /*  */
 
   function initProvide (vm) {
     var provide = vm.$options.provide;
     if (provide) {
       vm._provided = typeof provide === 'function'
         ? provide.call(vm)
         : provide;
     }
   }
 
   function initInjections (vm) {
     var result = resolveInject(vm.$options.inject, vm);
     if (result) {
       toggleObserving(false);
       Object.keys(result).forEach(function (key) {
         /* istanbul ignore else */
         {
           defineReactive$$1(vm, key, result[key], function () {
             warn(
               "Avoid mutating an injected value directly since the changes will be " +
               "overwritten whenever the provided component re-renders. " +
               "injection being mutated: \"" + key + "\"",
               vm
             );
           });
         }
       });
       toggleObserving(true);
     }
   }
 
   function resolveInject (inject, vm) {
     if (inject) {
       // inject is :any because flow is not smart enough to figure out cached
       var result = Object.create(null);
       var keys = hasSymbol
         ? Reflect.ownKeys(inject)
         : Object.keys(inject);
 
       for (var i = 0; i < keys.length; i++) {
         var key = keys[i];
         // #6574 in case the inject object is observed...
         if (key === '__ob__') { continue }
         var provideKey = inject[key].from;
         var source = vm;
         while (source) {
           if (source._provided && hasOwn(source._provided, provideKey)) {
             result[key] = source._provided[provideKey];
             break
           }
           source = source.$parent;
         }
         if (!source) {
           if ('default' in inject[key]) {
             var provideDefault = inject[key].default;
             result[key] = typeof provideDefault === 'function'
               ? provideDefault.call(vm)
               : provideDefault;
           } else {
             warn(("Injection \"" + key + "\" not found"), vm);
           }
         }
       }
       return result
     }
   }
 
   /*  */
 
 
 
   /**
    * Runtime helper for resolving raw children VNodes into a slot object.
    */
   function resolveSlots (
     children,
     context
   ) {
     if (!children || !children.length) {
       return {}
     }
     var slots = {};
     for (var i = 0, l = children.length; i < l; i++) {
       var child = children[i];
       var data = child.data;
       // remove slot attribute if the node is resolved as a Vue slot node
       if (data && data.attrs && data.attrs.slot) {
         delete data.attrs.slot;
       }
       // named slots should only be respected if the vnode was rendered in the
       // same context.
       if ((child.context === context || child.fnContext === context) &&
         data && data.slot != null
       ) {
         var name = data.slot;
         var slot = (slots[name] || (slots[name] = []));
         if (child.tag === 'template') {
           slot.push.apply(slot, child.children || []);
         } else {
           slot.push(child);
         }
       } else {
         (slots.default || (slots.default = [])).push(child);
       }
     }
     // ignore slots that contains only whitespace
     for (var name$1 in slots) {
       if (slots[name$1].every(isWhitespace)) {
         delete slots[name$1];
       }
     }
     return slots
   }
 
   function isWhitespace (node) {
     return (node.isComment && !node.asyncFactory) || node.text === ' '
   }
 
   /*  */
 
   function normalizeScopedSlots (
     slots,
     normalSlots,
     prevSlots
   ) {
     var res;
     var hasNormalSlots = Object.keys(normalSlots).length > 0;
     var isStable = slots ? !!slots.$stable : !hasNormalSlots;
     var key = slots && slots.$key;
     if (!slots) {
       res = {};
     } else if (slots._normalized) {
       // fast path 1: child component re-render only, parent did not change
       return slots._normalized
     } else if (
       isStable &&
       prevSlots &&
       prevSlots !== emptyObject &&
       key === prevSlots.$key &&
       !hasNormalSlots &&
       !prevSlots.$hasNormal
     ) {
       // fast path 2: stable scoped slots w/ no normal slots to proxy,
       // only need to normalize once
       return prevSlots
     } else {
       res = {};
       for (var key$1 in slots) {
         if (slots[key$1] && key$1[0] !== '$') {
           res[key$1] = normalizeScopedSlot(normalSlots, key$1, slots[key$1]);
         }
       }
     }
     // expose normal slots on scopedSlots
     for (var key$2 in normalSlots) {
       if (!(key$2 in res)) {
         res[key$2] = proxyNormalSlot(normalSlots, key$2);
       }
     }
     // avoriaz seems to mock a non-extensible $scopedSlots object
     // and when that is passed down this would cause an error
     if (slots && Object.isExtensible(slots)) {
       (slots)._normalized = res;
     }
     def(res, '$stable', isStable);
     def(res, '$key', key);
     def(res, '$hasNormal', hasNormalSlots);
     return res
   }
 
   function normalizeScopedSlot(normalSlots, key, fn) {
     var normalized = function () {
       var res = arguments.length ? fn.apply(null, arguments) : fn({});
       res = res && typeof res === 'object' && !Array.isArray(res)
         ? [res] // single vnode
         : normalizeChildren(res);
       return res && (
         res.length === 0 ||
         (res.length === 1 && res[0].isComment) // #9658
       ) ? undefined
         : res
     };
     // this is a slot using the new v-slot syntax without scope. although it is
     // compiled as a scoped slot, render fn users would expect it to be present
     // on this.$slots because the usage is semantically a normal slot.
     if (fn.proxy) {
       Object.defineProperty(normalSlots, key, {
         get: normalized,
         enumerable: true,
         configurable: true
       });
     }
     return normalized
   }
 
   function proxyNormalSlot(slots, key) {
     return function () { return slots[key]; }
   }
 
   /*  */
 
   /**
    * Runtime helper for rendering v-for lists.
    */
   function renderList (
     val,
     render
   ) {
     var ret, i, l, keys, key;
     if (Array.isArray(val) || typeof val === 'string') {
       ret = new Array(val.length);
       for (i = 0, l = val.length; i < l; i++) {
         ret[i] = render(val[i], i);
       }
     } else if (typeof val === 'number') {
       ret = new Array(val);
       for (i = 0; i < val; i++) {
         ret[i] = render(i + 1, i);
       }
     } else if (isObject(val)) {
       if (hasSymbol && val[Symbol.iterator]) {
         ret = [];
         var iterator = val[Symbol.iterator]();
         var result = iterator.next();
         while (!result.done) {
           ret.push(render(result.value, ret.length));
           result = iterator.next();
         }
       } else {
         keys = Object.keys(val);
         ret = new Array(keys.length);
         for (i = 0, l = keys.length; i < l; i++) {
           key = keys[i];
           ret[i] = render(val[key], key, i);
         }
       }
     }
     if (!isDef(ret)) {
       ret = [];
     }
     (ret)._isVList = true;
     return ret
   }
 
   /*  */
 
   /**
    * Runtime helper for rendering <slot>
    */
   function renderSlot (
     name,
     fallback,
     props,
     bindObject
   ) {
     var scopedSlotFn = this.$scopedSlots[name];
     var nodes;
     if (scopedSlotFn) { // scoped slot
       props = props || {};
       if (bindObject) {
         if (!isObject(bindObject)) {
           warn(
             'slot v-bind without argument expects an Object',
             this
           );
         }
         props = extend(extend({}, bindObject), props);
       }
       nodes = scopedSlotFn(props) || fallback;
     } else {
       nodes = this.$slots[name] || fallback;
     }
 
     var target = props && props.slot;
     if (target) {
       return this.$createElement('template', { slot: target }, nodes)
     } else {
       return nodes
     }
   }
 
   /*  */
 
   /**
    * Runtime helper for resolving filters
    */
   function resolveFilter (id) {
     return resolveAsset(this.$options, 'filters', id, true) || identity
   }
 
   /*  */
 
   function isKeyNotMatch (expect, actual) {
     if (Array.isArray(expect)) {
       return expect.indexOf(actual) === -1
     } else {
       return expect !== actual
     }
   }
 
   /**
    * Runtime helper for checking keyCodes from config.
    * exposed as Vue.prototype._k
    * passing in eventKeyName as last argument separately for backwards compat
    */
   function checkKeyCodes (
     eventKeyCode,
     key,
     builtInKeyCode,
     eventKeyName,
     builtInKeyName
   ) {
     var mappedKeyCode = config.keyCodes[key] || builtInKeyCode;
     if (builtInKeyName && eventKeyName && !config.keyCodes[key]) {
       return isKeyNotMatch(builtInKeyName, eventKeyName)
     } else if (mappedKeyCode) {
       return isKeyNotMatch(mappedKeyCode, eventKeyCode)
     } else if (eventKeyName) {
       return hyphenate(eventKeyName) !== key
     }
   }
 
   /*  */
 
   /**
    * Runtime helper for merging v-bind="object" into a VNode's data.
    */
   function bindObjectProps (
     data,
     tag,
     value,
     asProp,
     isSync
   ) {
     if (value) {
       if (!isObject(value)) {
         warn(
           'v-bind without argument expects an Object or Array value',
           this
         );
       } else {
         if (Array.isArray(value)) {
           value = toObject(value);
         }
         var hash;
         var loop = function ( key ) {
           if (
             key === 'class' ||
             key === 'style' ||
             isReservedAttribute(key)
           ) {
             hash = data;
           } else {
             var type = data.attrs && data.attrs.type;
             hash = asProp || config.mustUseProp(tag, type, key)
               ? data.domProps || (data.domProps = {})
               : data.attrs || (data.attrs = {});
           }
           var camelizedKey = camelize(key);
           var hyphenatedKey = hyphenate(key);
           if (!(camelizedKey in hash) && !(hyphenatedKey in hash)) {
             hash[key] = value[key];
 
             if (isSync) {
               var on = data.on || (data.on = {});
               on[("update:" + key)] = function ($event) {
                 value[key] = $event;
               };
             }
           }
         };
 
         for (var key in value) loop( key );
       }
     }
     return data
   }
 
   /*  */
 
   /**
    * Runtime helper for rendering static trees.
    */
   function renderStatic (
     index,
     isInFor
   ) {
     var cached = this._staticTrees || (this._staticTrees = []);
     var tree = cached[index];
     // if has already-rendered static tree and not inside v-for,
     // we can reuse the same tree.
     if (tree && !isInFor) {
       return tree
     }
     // otherwise, render a fresh tree.
     tree = cached[index] = this.$options.staticRenderFns[index].call(
       this._renderProxy,
       null,
       this // for render fns generated for functional component templates
     );
     markStatic(tree, ("__static__" + index), false);
     return tree
   }
 
   /**
    * Runtime helper for v-once.
    * Effectively it means marking the node as static with a unique key.
    */
   function markOnce (
     tree,
     index,
     key
   ) {
     markStatic(tree, ("__once__" + index + (key ? ("_" + key) : "")), true);
     return tree
   }
 
   function markStatic (
     tree,
     key,
     isOnce
   ) {
     if (Array.isArray(tree)) {
       for (var i = 0; i < tree.length; i++) {
         if (tree[i] && typeof tree[i] !== 'string') {
           markStaticNode(tree[i], (key + "_" + i), isOnce);
         }
       }
     } else {
       markStaticNode(tree, key, isOnce);
     }
   }
 
   function markStaticNode (node, key, isOnce) {
     node.isStatic = true;
     node.key = key;
     node.isOnce = isOnce;
   }
 
   /*  */
 
   function bindObjectListeners (data, value) {
     if (value) {
       if (!isPlainObject(value)) {
         warn(
           'v-on without argument expects an Object value',
           this
         );
       } else {
         var on = data.on = data.on ? extend({}, data.on) : {};
         for (var key in value) {
           var existing = on[key];
           var ours = value[key];
           on[key] = existing ? [].concat(existing, ours) : ours;
         }
       }
     }
     return data
   }
 
   /*  */
 
   function resolveScopedSlots (
     fns, // see flow/vnode
     res,
     // the following are added in 2.6
     hasDynamicKeys,
     contentHashKey
   ) {
     res = res || { $stable: !hasDynamicKeys };
     for (var i = 0; i < fns.length; i++) {
       var slot = fns[i];
       if (Array.isArray(slot)) {
         resolveScopedSlots(slot, res, hasDynamicKeys);
       } else if (slot) {
         // marker for reverse proxying v-slot without scope on this.$slots
         if (slot.proxy) {
           slot.fn.proxy = true;
         }
         res[slot.key] = slot.fn;
       }
     }
     if (contentHashKey) {
       (res).$key = contentHashKey;
     }
     return res
   }
 
   /*  */
 
   function bindDynamicKeys (baseObj, values) {
     for (var i = 0; i < values.length; i += 2) {
       var key = values[i];
       if (typeof key === 'string' && key) {
         baseObj[values[i]] = values[i + 1];
       } else if (key !== '' && key !== null) {
         // null is a special value for explicitly removing a binding
         warn(
           ("Invalid value for dynamic directive argument (expected string or null): " + key),
           this
         );
       }
     }
     return baseObj
   }
 
   // helper to dynamically append modifier runtime markers to event names.
   // ensure only append when value is already string, otherwise it will be cast
   // to string and cause the type check to miss.
   function prependModifier (value, symbol) {
     return typeof value === 'string' ? symbol + value : value
   }
 
   /*  */
 
   function installRenderHelpers (target) {
     target._o = markOnce;
     target._n = toNumber;
     target._s = toString;
     target._l = renderList;
     target._t = renderSlot;
     target._q = looseEqual;
     target._i = looseIndexOf;
     target._m = renderStatic;
     target._f = resolveFilter;
     target._k = checkKeyCodes;
     target._b = bindObjectProps;
     target._v = createTextVNode;
     target._e = createEmptyVNode;
     target._u = resolveScopedSlots;
     target._g = bindObjectListeners;
     target._d = bindDynamicKeys;
     target._p = prependModifier;
   }
 
   /*  */
 
   function FunctionalRenderContext (
     data,
     props,
     children,
     parent,
     Ctor
   ) {
     var this$1 = this;
 
     var options = Ctor.options;
     // ensure the createElement function in functional components
     // gets a unique context - this is necessary for correct named slot check
     var contextVm;
     if (hasOwn(parent, '_uid')) {
       contextVm = Object.create(parent);
       // $flow-disable-line
       contextVm._original = parent;
     } else {
       // the context vm passed in is a functional context as well.
       // in this case we want to make sure we are able to get a hold to the
       // real context instance.
       contextVm = parent;
       // $flow-disable-line
       parent = parent._original;
     }
     var isCompiled = isTrue(options._compiled);
     var needNormalization = !isCompiled;
 
     this.data = data;
     this.props = props;
     this.children = children;
     this.parent = parent;
     this.listeners = data.on || emptyObject;
     this.injections = resolveInject(options.inject, parent);
     this.slots = function () {
       if (!this$1.$slots) {
         normalizeScopedSlots(
           data.scopedSlots,
           this$1.$slots = resolveSlots(children, parent)
         );
       }
       return this$1.$slots
     };
 
     Object.defineProperty(this, 'scopedSlots', ({
       enumerable: true,
       get: function get () {
         return normalizeScopedSlots(data.scopedSlots, this.slots())
       }
     }));
 
     // support for compiled functional template
     if (isCompiled) {
       // exposing $options for renderStatic()
       this.$options = options;
       // pre-resolve slots for renderSlot()
       this.$slots = this.slots();
       this.$scopedSlots = normalizeScopedSlots(data.scopedSlots, this.$slots);
     }
 
     if (options._scopeId) {
       this._c = function (a, b, c, d) {
         var vnode = createElement(contextVm, a, b, c, d, needNormalization);
         if (vnode && !Array.isArray(vnode)) {
           vnode.fnScopeId = options._scopeId;
           vnode.fnContext = parent;
         }
         return vnode
       };
     } else {
       this._c = function (a, b, c, d) { return createElement(contextVm, a, b, c, d, needNormalization); };
     }
   }
 
   installRenderHelpers(FunctionalRenderContext.prototype);
 
   function createFunctionalComponent (
     Ctor,
     propsData,
     data,
     contextVm,
     children
   ) {
     var options = Ctor.options;
     var props = {};
     var propOptions = options.props;
     if (isDef(propOptions)) {
       for (var key in propOptions) {
         props[key] = validateProp(key, propOptions, propsData || emptyObject);
       }
     } else {
       if (isDef(data.attrs)) { mergeProps(props, data.attrs); }
       if (isDef(data.props)) { mergeProps(props, data.props); }
     }
 
     var renderContext = new FunctionalRenderContext(
       data,
       props,
       children,
       contextVm,
       Ctor
     );
 
     var vnode = options.render.call(null, renderContext._c, renderContext);
 
     if (vnode instanceof VNode) {
       return cloneAndMarkFunctionalResult(vnode, data, renderContext.parent, options, renderContext)
     } else if (Array.isArray(vnode)) {
       var vnodes = normalizeChildren(vnode) || [];
       var res = new Array(vnodes.length);
       for (var i = 0; i < vnodes.length; i++) {
         res[i] = cloneAndMarkFunctionalResult(vnodes[i], data, renderContext.parent, options, renderContext);
       }
       return res
     }
   }
 
   function cloneAndMarkFunctionalResult (vnode, data, contextVm, options, renderContext) {
     // #7817 clone node before setting fnContext, otherwise if the node is reused
     // (e.g. it was from a cached normal slot) the fnContext causes named slots
     // that should not be matched to match.
     var clone = cloneVNode(vnode);
     clone.fnContext = contextVm;
     clone.fnOptions = options;
     {
       (clone.devtoolsMeta = clone.devtoolsMeta || {}).renderContext = renderContext;
     }
     if (data.slot) {
       (clone.data || (clone.data = {})).slot = data.slot;
     }
     return clone
   }
 
   function mergeProps (to, from) {
     for (var key in from) {
       to[camelize(key)] = from[key];
     }
   }
 
   /*  */
 
   /*  */
 
   /*  */
 
   /*  */
 
   // inline hooks to be invoked on component VNodes during patch
   var componentVNodeHooks = {
     init: function init (vnode, hydrating) {
       if (
         vnode.componentInstance &&
         !vnode.componentInstance._isDestroyed &&
         vnode.data.keepAlive
       ) {
         // kept-alive components, treat as a patch
         var mountedNode = vnode; // work around flow
         componentVNodeHooks.prepatch(mountedNode, mountedNode);
       } else {
         var child = vnode.componentInstance = createComponentInstanceForVnode(
           vnode,
           activeInstance
         );
         child.$mount(hydrating ? vnode.elm : undefined, hydrating);
       }
     },
 
     prepatch: function prepatch (oldVnode, vnode) {
       var options = vnode.componentOptions;
       var child = vnode.componentInstance = oldVnode.componentInstance;
       updateChildComponent(
         child,
         options.propsData, // updated props
         options.listeners, // updated listeners
         vnode, // new parent vnode
         options.children // new children
       );
     },
 
     insert: function insert (vnode) {
       var context = vnode.context;
       var componentInstance = vnode.componentInstance;
       if (!componentInstance._isMounted) {
         componentInstance._isMounted = true;
         callHook(componentInstance, 'mounted');
       }
       if (vnode.data.keepAlive) {
         if (context._isMounted) {
           // vue-router#1212
           // During updates, a kept-alive component's child components may
           // change, so directly walking the tree here may call activated hooks
           // on incorrect children. Instead we push them into a queue which will
           // be processed after the whole patch process ended.
           queueActivatedComponent(componentInstance);
         } else {
           activateChildComponent(componentInstance, true /* direct */);
         }
       }
     },
 
     destroy: function destroy (vnode) {
       var componentInstance = vnode.componentInstance;
       if (!componentInstance._isDestroyed) {
         if (!vnode.data.keepAlive) {
           componentInstance.$destroy();
         } else {
           deactivateChildComponent(componentInstance, true /* direct */);
         }
       }
     }
   };
 
   var hooksToMerge = Object.keys(componentVNodeHooks);
 
   function createComponent (
     Ctor,
     data,
     context,
     children,
     tag
   ) {
     if (isUndef(Ctor)) {
       return
     }
 
     var baseCtor = context.$options._base;
 
     // plain options object: turn it into a constructor
     if (isObject(Ctor)) {
       Ctor = baseCtor.extend(Ctor);
     }
 
     // if at this stage it's not a constructor or an async component factory,
     // reject.
     if (typeof Ctor !== 'function') {
       {
         warn(("Invalid Component definition: " + (String(Ctor))), context);
       }
       return
     }
 
     // async component
     var asyncFactory;
     if (isUndef(Ctor.cid)) {
       asyncFactory = Ctor;
       Ctor = resolveAsyncComponent(asyncFactory, baseCtor);
       if (Ctor === undefined) {
         // return a placeholder node for async component, which is rendered
         // as a comment node but preserves all the raw information for the node.
         // the information will be used for async server-rendering and hydration.
         return createAsyncPlaceholder(
           asyncFactory,
           data,
           context,
           children,
           tag
         )
       }
     }
 
     data = data || {};
 
     // resolve constructor options in case global mixins are applied after
     // component constructor creation
     resolveConstructorOptions(Ctor);
 
     // transform component v-model data into props & events
     if (isDef(data.model)) {
       transformModel(Ctor.options, data);
     }
 
     // extract props
     var propsData = extractPropsFromVNodeData(data, Ctor, tag);
 
     // functional component
     if (isTrue(Ctor.options.functional)) {
       return createFunctionalComponent(Ctor, propsData, data, context, children)
     }
 
     // extract listeners, since these needs to be treated as
     // child component listeners instead of DOM listeners
     var listeners = data.on;
     // replace with listeners with .native modifier
     // so it gets processed during parent component patch.
     data.on = data.nativeOn;
 
     if (isTrue(Ctor.options.abstract)) {
       // abstract components do not keep anything
       // other than props & listeners & slot
 
       // work around flow
       var slot = data.slot;
       data = {};
       if (slot) {
         data.slot = slot;
       }
     }
 
     // install component management hooks onto the placeholder node
     installComponentHooks(data);
 
     // return a placeholder vnode
     var name = Ctor.options.name || tag;
     var vnode = new VNode(
       ("vue-component-" + (Ctor.cid) + (name ? ("-" + name) : '')),
       data, undefined, undefined, undefined, context,
       { Ctor: Ctor, propsData: propsData, listeners: listeners, tag: tag, children: children },
       asyncFactory
     );
 
     return vnode
   }
 
   function createComponentInstanceForVnode (
     vnode, // we know it's MountedComponentVNode but flow doesn't
     parent // activeInstance in lifecycle state
   ) {
     var options = {
       _isComponent: true,
       _parentVnode: vnode,
       parent: parent
     };
     // check inline-template render functions
     var inlineTemplate = vnode.data.inlineTemplate;
     if (isDef(inlineTemplate)) {
       options.render = inlineTemplate.render;
       options.staticRenderFns = inlineTemplate.staticRenderFns;
     }
     return new vnode.componentOptions.Ctor(options)
   }
 
   function installComponentHooks (data) {
     var hooks = data.hook || (data.hook = {});
     for (var i = 0; i < hooksToMerge.length; i++) {
       var key = hooksToMerge[i];
       var existing = hooks[key];
       var toMerge = componentVNodeHooks[key];
       if (existing !== toMerge && !(existing && existing._merged)) {
         hooks[key] = existing ? mergeHook$1(toMerge, existing) : toMerge;
       }
     }
   }
 
   function mergeHook$1 (f1, f2) {
     var merged = function (a, b) {
       // flow complains about extra args which is why we use any
       f1(a, b);
       f2(a, b);
     };
     merged._merged = true;
     return merged
   }
 
   // transform component v-model info (value and callback) into
   // prop and event handler respectively.
   function transformModel (options, data) {
     var prop = (options.model && options.model.prop) || 'value';
     var event = (options.model && options.model.event) || 'input'
     ;(data.attrs || (data.attrs = {}))[prop] = data.model.value;
     var on = data.on || (data.on = {});
     var existing = on[event];
     var callback = data.model.callback;
     if (isDef(existing)) {
       if (
         Array.isArray(existing)
           ? existing.indexOf(callback) === -1
           : existing !== callback
       ) {
         on[event] = [callback].concat(existing);
       }
     } else {
       on[event] = callback;
     }
   }
 
   /*  */
 
   var SIMPLE_NORMALIZE = 1;
   var ALWAYS_NORMALIZE = 2;
 
   // wrapper function for providing a more flexible interface
   // without getting yelled at by flow
   function createElement (
     context,
     tag,
     data,
     children,
     normalizationType,
     alwaysNormalize
   ) {
     if (Array.isArray(data) || isPrimitive(data)) {
       normalizationType = children;
       children = data;
       data = undefined;
     }
     if (isTrue(alwaysNormalize)) {
       normalizationType = ALWAYS_NORMALIZE;
     }
     return _createElement(context, tag, data, children, normalizationType)
   }
 
   function _createElement (
     context,
     tag,
     data,
     children,
     normalizationType
   ) {
     if (isDef(data) && isDef((data).__ob__)) {
       warn(
         "Avoid using observed data object as vnode data: " + (JSON.stringify(data)) + "\n" +
         'Always create fresh vnode data objects in each render!',
         context
       );
       return createEmptyVNode()
     }
     // object syntax in v-bind
     if (isDef(data) && isDef(data.is)) {
       tag = data.is;
     }
     if (!tag) {
       // in case of component :is set to falsy value
       return createEmptyVNode()
     }
     // warn against non-primitive key
     if (isDef(data) && isDef(data.key) && !isPrimitive(data.key)
     ) {
       {
         warn(
           'Avoid using non-primitive value as key, ' +
           'use string/number value instead.',
           context
         );
       }
     }
     // support single function children as default scoped slot
     if (Array.isArray(children) &&
       typeof children[0] === 'function'
     ) {
       data = data || {};
       data.scopedSlots = { default: children[0] };
       children.length = 0;
     }
     if (normalizationType === ALWAYS_NORMALIZE) {
       children = normalizeChildren(children);
     } else if (normalizationType === SIMPLE_NORMALIZE) {
       children = simpleNormalizeChildren(children);
     }
     var vnode, ns;
     if (typeof tag === 'string') {
       var Ctor;
       ns = (context.$vnode && context.$vnode.ns) || config.getTagNamespace(tag);
       if (config.isReservedTag(tag)) {
         // platform built-in elements
         if (isDef(data) && isDef(data.nativeOn)) {
           warn(
             ("The .native modifier for v-on is only valid on components but it was used on <" + tag + ">."),
             context
           );
         }
         vnode = new VNode(
           config.parsePlatformTagName(tag), data, children,
           undefined, undefined, context
         );
       } else if ((!data || !data.pre) && isDef(Ctor = resolveAsset(context.$options, 'components', tag))) {
         // component
         vnode = createComponent(Ctor, data, context, children, tag);
       } else {
         // unknown or unlisted namespaced elements
         // check at runtime because it may get assigned a namespace when its
         // parent normalizes children
         vnode = new VNode(
           tag, data, children,
           undefined, undefined, context
         );
       }
     } else {
       // direct component options / constructor
       vnode = createComponent(tag, data, context, children);
     }
     if (Array.isArray(vnode)) {
       return vnode
     } else if (isDef(vnode)) {
       if (isDef(ns)) { applyNS(vnode, ns); }
       if (isDef(data)) { registerDeepBindings(data); }
       return vnode
     } else {
       return createEmptyVNode()
     }
   }
 
   function applyNS (vnode, ns, force) {
     vnode.ns = ns;
     if (vnode.tag === 'foreignObject') {
       // use default namespace inside foreignObject
       ns = undefined;
       force = true;
     }
     if (isDef(vnode.children)) {
       for (var i = 0, l = vnode.children.length; i < l; i++) {
         var child = vnode.children[i];
         if (isDef(child.tag) && (
           isUndef(child.ns) || (isTrue(force) && child.tag !== 'svg'))) {
           applyNS(child, ns, force);
         }
       }
     }
   }
 
   // ref #5318
   // necessary to ensure parent re-render when deep bindings like :style and
   // :class are used on slot nodes
   function registerDeepBindings (data) {
     if (isObject(data.style)) {
       traverse(data.style);
     }
     if (isObject(data.class)) {
       traverse(data.class);
     }
   }
 
   /*  */
 
   function initRender (vm) {
     vm._vnode = null; // the root of the child tree
     vm._staticTrees = null; // v-once cached trees
     var options = vm.$options;
     var parentVnode = vm.$vnode = options._parentVnode; // the placeholder node in parent tree
     var renderContext = parentVnode && parentVnode.context;
     vm.$slots = resolveSlots(options._renderChildren, renderContext);
     vm.$scopedSlots = emptyObject;
     // bind the createElement fn to this instance
     // so that we get proper render context inside it.
     // args order: tag, data, children, normalizationType, alwaysNormalize
     // internal version is used by render functions compiled from templates
     vm._c = function (a, b, c, d) { return createElement(vm, a, b, c, d, false); };
     // normalization is always applied for the public version, used in
     // user-written render functions.
     vm.$createElement = function (a, b, c, d) { return createElement(vm, a, b, c, d, true); };
 
     // $attrs & $listeners are exposed for easier HOC creation.
     // they need to be reactive so that HOCs using them are always updated
     var parentData = parentVnode && parentVnode.data;
 
     /* istanbul ignore else */
     {
       defineReactive$$1(vm, '$attrs', parentData && parentData.attrs || emptyObject, function () {
         !isUpdatingChildComponent && warn("$attrs is readonly.", vm);
       }, true);
       defineReactive$$1(vm, '$listeners', options._parentListeners || emptyObject, function () {
         !isUpdatingChildComponent && warn("$listeners is readonly.", vm);
       }, true);
     }
   }
 
   var currentRenderingInstance = null;
 
   function renderMixin (Vue) {
     // install runtime convenience helpers
     installRenderHelpers(Vue.prototype);
 
     Vue.prototype.$nextTick = function (fn) {
       return nextTick(fn, this)
     };
 
     Vue.prototype._render = function () {
       var vm = this;
       var ref = vm.$options;
       var render = ref.render;
       var _parentVnode = ref._parentVnode;
 
       if (_parentVnode) {
         vm.$scopedSlots = normalizeScopedSlots(
           _parentVnode.data.scopedSlots,
           vm.$slots,
           vm.$scopedSlots
         );
       }
 
       // set parent vnode. this allows render functions to have access
       // to the data on the placeholder node.
       vm.$vnode = _parentVnode;
       // render self
       var vnode;
       try {
         // There's no need to maintain a stack because all render fns are called
         // separately from one another. Nested component's render fns are called
         // when parent component is patched.
         currentRenderingInstance = vm;
         vnode = render.call(vm._renderProxy, vm.$createElement);
       } catch (e) {
         handleError(e, vm, "render");
         // return error render result,
         // or previous vnode to prevent render error causing blank component
         /* istanbul ignore else */
         if (vm.$options.renderError) {
           try {
             vnode = vm.$options.renderError.call(vm._renderProxy, vm.$createElement, e);
           } catch (e) {
             handleError(e, vm, "renderError");
             vnode = vm._vnode;
           }
         } else {
           vnode = vm._vnode;
         }
       } finally {
         currentRenderingInstance = null;
       }
       // if the returned array contains only a single node, allow it
       if (Array.isArray(vnode) && vnode.length === 1) {
         vnode = vnode[0];
       }
       // return empty vnode in case the render function errored out
       if (!(vnode instanceof VNode)) {
         if (Array.isArray(vnode)) {
           warn(
             'Multiple root nodes returned from render function. Render function ' +
             'should return a single root node.',
             vm
           );
         }
         vnode = createEmptyVNode();
       }
       // set parent
       vnode.parent = _parentVnode;
       return vnode
     };
   }
 
   /*  */
 
   function ensureCtor (comp, base) {
     if (
       comp.__esModule ||
       (hasSymbol && comp[Symbol.toStringTag] === 'Module')
     ) {
       comp = comp.default;
     }
     return isObject(comp)
       ? base.extend(comp)
       : comp
   }
 
   function createAsyncPlaceholder (
     factory,
     data,
     context,
     children,
     tag
   ) {
     var node = createEmptyVNode();
     node.asyncFactory = factory;
     node.asyncMeta = { data: data, context: context, children: children, tag: tag };
     return node
   }
 
   function resolveAsyncComponent (
     factory,
     baseCtor
   ) {
     if (isTrue(factory.error) && isDef(factory.errorComp)) {
       return factory.errorComp
     }
 
     if (isDef(factory.resolved)) {
       return factory.resolved
     }
 
     var owner = currentRenderingInstance;
     if (owner && isDef(factory.owners) && factory.owners.indexOf(owner) === -1) {
       // already pending
       factory.owners.push(owner);
     }
 
     if (isTrue(factory.loading) && isDef(factory.loadingComp)) {
       return factory.loadingComp
     }
 
     if (owner && !isDef(factory.owners)) {
       var owners = factory.owners = [owner];
       var sync = true;
       var timerLoading = null;
       var timerTimeout = null
 
       ;(owner).$on('hook:destroyed', function () { return remove(owners, owner); });
 
       var forceRender = function (renderCompleted) {
         for (var i = 0, l = owners.length; i < l; i++) {
           (owners[i]).$forceUpdate();
         }
 
         if (renderCompleted) {
           owners.length = 0;
           if (timerLoading !== null) {
             clearTimeout(timerLoading);
             timerLoading = null;
           }
           if (timerTimeout !== null) {
             clearTimeout(timerTimeout);
             timerTimeout = null;
           }
         }
       };
 
       var resolve = once(function (res) {
         // cache resolved
         factory.resolved = ensureCtor(res, baseCtor);
         // invoke callbacks only if this is not a synchronous resolve
         // (async resolves are shimmed as synchronous during SSR)
         if (!sync) {
           forceRender(true);
         } else {
           owners.length = 0;
         }
       });
 
       var reject = once(function (reason) {
         warn(
           "Failed to resolve async component: " + (String(factory)) +
           (reason ? ("\nReason: " + reason) : '')
         );
         if (isDef(factory.errorComp)) {
           factory.error = true;
           forceRender(true);
         }
       });
 
       var res = factory(resolve, reject);
 
       if (isObject(res)) {
         if (isPromise(res)) {
           // () => Promise
           if (isUndef(factory.resolved)) {
             res.then(resolve, reject);
           }
         } else if (isPromise(res.component)) {
           res.component.then(resolve, reject);
 
           if (isDef(res.error)) {
             factory.errorComp = ensureCtor(res.error, baseCtor);
           }
 
           if (isDef(res.loading)) {
             factory.loadingComp = ensureCtor(res.loading, baseCtor);
             if (res.delay === 0) {
               factory.loading = true;
             } else {
               timerLoading = setTimeout(function () {
                 timerLoading = null;
                 if (isUndef(factory.resolved) && isUndef(factory.error)) {
                   factory.loading = true;
                   forceRender(false);
                 }
               }, res.delay || 200);
             }
           }
 
           if (isDef(res.timeout)) {
             timerTimeout = setTimeout(function () {
               timerTimeout = null;
               if (isUndef(factory.resolved)) {
                 reject(
                   "timeout (" + (res.timeout) + "ms)"
                 );
               }
             }, res.timeout);
           }
         }
       }
 
       sync = false;
       // return in case resolved synchronously
       return factory.loading
         ? factory.loadingComp
         : factory.resolved
     }
   }
 
   /*  */
 
   function isAsyncPlaceholder (node) {
     return node.isComment && node.asyncFactory
   }
 
   /*  */
 
   function getFirstComponentChild (children) {
     if (Array.isArray(children)) {
       for (var i = 0; i < children.length; i++) {
         var c = children[i];
         if (isDef(c) && (isDef(c.componentOptions) || isAsyncPlaceholder(c))) {
           return c
         }
       }
     }
   }
 
   /*  */
 
   /*  */
 
   function initEvents (vm) {
     vm._events = Object.create(null);
     vm._hasHookEvent = false;
     // init parent attached events
     var listeners = vm.$options._parentListeners;
     if (listeners) {
       updateComponentListeners(vm, listeners);
     }
   }
 
   var target;
 
   function add (event, fn) {
     target.$on(event, fn);
   }
 
   function remove$1 (event, fn) {
     target.$off(event, fn);
   }
 
   function createOnceHandler (event, fn) {
     var _target = target;
     return function onceHandler () {
       var res = fn.apply(null, arguments);
       if (res !== null) {
         _target.$off(event, onceHandler);
       }
     }
   }
 
   function updateComponentListeners (
     vm,
     listeners,
     oldListeners
   ) {
     target = vm;
     updateListeners(listeners, oldListeners || {}, add, remove$1, createOnceHandler, vm);
     target = undefined;
   }
 
   function eventsMixin (Vue) {
     var hookRE = /^hook:/;
     Vue.prototype.$on = function (event, fn) {
       var vm = this;
       if (Array.isArray(event)) {
         for (var i = 0, l = event.length; i < l; i++) {
           vm.$on(event[i], fn);
         }
       } else {
         (vm._events[event] || (vm._events[event] = [])).push(fn);
         // optimize hook:event cost by using a boolean flag marked at registration
         // instead of a hash lookup
         if (hookRE.test(event)) {
           vm._hasHookEvent = true;
         }
       }
       return vm
     };
 
     Vue.prototype.$once = function (event, fn) {
       var vm = this;
       function on () {
         vm.$off(event, on);
         fn.apply(vm, arguments);
       }
       on.fn = fn;
       vm.$on(event, on);
       return vm
     };
 
     Vue.prototype.$off = function (event, fn) {
       var vm = this;
       // all
       if (!arguments.length) {
         vm._events = Object.create(null);
         return vm
       }
       // array of events
       if (Array.isArray(event)) {
         for (var i$1 = 0, l = event.length; i$1 < l; i$1++) {
           vm.$off(event[i$1], fn);
         }
         return vm
       }
       // specific event
       var cbs = vm._events[event];
       if (!cbs) {
         return vm
       }
       if (!fn) {
         vm._events[event] = null;
         return vm
       }
       // specific handler
       var cb;
       var i = cbs.length;
       while (i--) {
         cb = cbs[i];
         if (cb === fn || cb.fn === fn) {
           cbs.splice(i, 1);
           break
         }
       }
       return vm
     };
 
     Vue.prototype.$emit = function (event) {
       var vm = this;
       {
         var lowerCaseEvent = event.toLowerCase();
         if (lowerCaseEvent !== event && vm._events[lowerCaseEvent]) {
           tip(
             "Event \"" + lowerCaseEvent + "\" is emitted in component " +
             (formatComponentName(vm)) + " but the handler is registered for \"" + event + "\". " +
             "Note that HTML attributes are case-insensitive and you cannot use " +
             "v-on to listen to camelCase events when using in-DOM templates. " +
             "You should probably use \"" + (hyphenate(event)) + "\" instead of \"" + event + "\"."
           );
         }
       }
       var cbs = vm._events[event];
       if (cbs) {
         cbs = cbs.length > 1 ? toArray(cbs) : cbs;
         var args = toArray(arguments, 1);
         var info = "event handler for \"" + event + "\"";
         for (var i = 0, l = cbs.length; i < l; i++) {
           invokeWithErrorHandling(cbs[i], vm, args, vm, info);
         }
       }
       return vm
     };
   }
 
   /*  */
 
   var activeInstance = null;
   var isUpdatingChildComponent = false;
 
   function setActiveInstance(vm) {
     var prevActiveInstance = activeInstance;
     activeInstance = vm;
     return function () {
       activeInstance = prevActiveInstance;
     }
   }
 
   function initLifecycle (vm) {
     var options = vm.$options;
 
     // locate first non-abstract parent
     var parent = options.parent;
     if (parent && !options.abstract) {
       while (parent.$options.abstract && parent.$parent) {
         parent = parent.$parent;
       }
       parent.$children.push(vm);
     }
 
     vm.$parent = parent;
     vm.$root = parent ? parent.$root : vm;
 
     vm.$children = [];
     vm.$refs = {};
 
     vm._watcher = null;
     vm._inactive = null;
     vm._directInactive = false;
     vm._isMounted = false;
     vm._isDestroyed = false;
     vm._isBeingDestroyed = false;
   }
 
   function lifecycleMixin (Vue) {
     Vue.prototype._update = function (vnode, hydrating) {
       var vm = this;
       var prevEl = vm.$el;
       var prevVnode = vm._vnode;
       var restoreActiveInstance = setActiveInstance(vm);
       vm._vnode = vnode;
       // Vue.prototype.__patch__ is injected in entry points
       // based on the rendering backend used.
       if (!prevVnode) {
         // initial render
         vm.$el = vm.__patch__(vm.$el, vnode, hydrating, false /* removeOnly */);
       } else {
         // updates
         vm.$el = vm.__patch__(prevVnode, vnode);
       }
       restoreActiveInstance();
       // update __vue__ reference
       if (prevEl) {
         prevEl.__vue__ = null;
       }
       if (vm.$el) {
         vm.$el.__vue__ = vm;
       }
       // if parent is an HOC, update its $el as well
       if (vm.$vnode && vm.$parent && vm.$vnode === vm.$parent._vnode) {
         vm.$parent.$el = vm.$el;
       }
       // updated hook is called by the scheduler to ensure that children are
       // updated in a parent's updated hook.
     };
 
     Vue.prototype.$forceUpdate = function () {
       var vm = this;
       if (vm._watcher) {
         vm._watcher.update();
       }
     };
 
     Vue.prototype.$destroy = function () {
       var vm = this;
       if (vm._isBeingDestroyed) {
         return
       }
       callHook(vm, 'beforeDestroy');
       vm._isBeingDestroyed = true;
       // remove self from parent
       var parent = vm.$parent;
       if (parent && !parent._isBeingDestroyed && !vm.$options.abstract) {
         remove(parent.$children, vm);
       }
       // teardown watchers
       if (vm._watcher) {
         vm._watcher.teardown();
       }
       var i = vm._watchers.length;
       while (i--) {
         vm._watchers[i].teardown();
       }
       // remove reference from data ob
       // frozen object may not have observer.
       if (vm._data.__ob__) {
         vm._data.__ob__.vmCount--;
       }
       // call the last hook...
       vm._isDestroyed = true;
       // invoke destroy hooks on current rendered tree
       vm.__patch__(vm._vnode, null);
       // fire destroyed hook
       callHook(vm, 'destroyed');
       // turn off all instance listeners.
       vm.$off();
       // remove __vue__ reference
       if (vm.$el) {
         vm.$el.__vue__ = null;
       }
       // release circular reference (#6759)
       if (vm.$vnode) {
         vm.$vnode.parent = null;
       }
     };
   }
 
   function mountComponent (
     vm,
     el,
     hydrating
   ) {
     vm.$el = el;
     if (!vm.$options.render) {
       vm.$options.render = createEmptyVNode;
       {
         /* istanbul ignore if */
         if ((vm.$options.template && vm.$options.template.charAt(0) !== '#') ||
           vm.$options.el || el) {
           warn(
             'You are using the runtime-only build of Vue where the template ' +
             'compiler is not available. Either pre-compile the templates into ' +
             'render functions, or use the compiler-included build.',
             vm
           );
         } else {
           warn(
             'Failed to mount component: template or render function not defined.',
             vm
           );
         }
       }
     }
     callHook(vm, 'beforeMount');
 
     var updateComponent;
     /* istanbul ignore if */
     if (config.performance && mark) {
       updateComponent = function () {
         var name = vm._name;
         var id = vm._uid;
         var startTag = "vue-perf-start:" + id;
         var endTag = "vue-perf-end:" + id;
 
         mark(startTag);
         var vnode = vm._render();
         mark(endTag);
         measure(("vue " + name + " render"), startTag, endTag);
 
         mark(startTag);
         vm._update(vnode, hydrating);
         mark(endTag);
         measure(("vue " + name + " patch"), startTag, endTag);
       };
     } else {
       updateComponent = function () {
         vm._update(vm._render(), hydrating);
       };
     }
 
     // we set this to vm._watcher inside the watcher's constructor
     // since the watcher's initial patch may call $forceUpdate (e.g. inside child
     // component's mounted hook), which relies on vm._watcher being already defined
     new Watcher(vm, updateComponent, noop, {
       before: function before () {
         if (vm._isMounted && !vm._isDestroyed) {
           callHook(vm, 'beforeUpdate');
         }
       }
     }, true /* isRenderWatcher */);
     hydrating = false;
 
     // manually mounted instance, call mounted on self
     // mounted is called for render-created child components in its inserted hook
     if (vm.$vnode == null) {
       vm._isMounted = true;
       callHook(vm, 'mounted');
     }
     return vm
   }
 
   function updateChildComponent (
     vm,
     propsData,
     listeners,
     parentVnode,
     renderChildren
   ) {
     {
       isUpdatingChildComponent = true;
     }
 
     // determine whether component has slot children
     // we need to do this before overwriting $options._renderChildren.
 
     // check if there are dynamic scopedSlots (hand-written or compiled but with
     // dynamic slot names). Static scoped slots compiled from template has the
     // "$stable" marker.
     var newScopedSlots = parentVnode.data.scopedSlots;
     var oldScopedSlots = vm.$scopedSlots;
     var hasDynamicScopedSlot = !!(
       (newScopedSlots && !newScopedSlots.$stable) ||
       (oldScopedSlots !== emptyObject && !oldScopedSlots.$stable) ||
       (newScopedSlots && vm.$scopedSlots.$key !== newScopedSlots.$key)
     );
 
     // Any static slot children from the parent may have changed during parent's
     // update. Dynamic scoped slots may also have changed. In such cases, a forced
     // update is necessary to ensure correctness.
     var needsForceUpdate = !!(
       renderChildren ||               // has new static slots
       vm.$options._renderChildren ||  // has old static slots
       hasDynamicScopedSlot
     );
 
     vm.$options._parentVnode = parentVnode;
     vm.$vnode = parentVnode; // update vm's placeholder node without re-render
 
     if (vm._vnode) { // update child tree's parent
       vm._vnode.parent = parentVnode;
     }
     vm.$options._renderChildren = renderChildren;
 
     // update $attrs and $listeners hash
     // these are also reactive so they may trigger child update if the child
     // used them during render
     vm.$attrs = parentVnode.data.attrs || emptyObject;
     vm.$listeners = listeners || emptyObject;
 
     // update props
     if (propsData && vm.$options.props) {
       toggleObserving(false);
       var props = vm._props;
       var propKeys = vm.$options._propKeys || [];
       for (var i = 0; i < propKeys.length; i++) {
         var key = propKeys[i];
         var propOptions = vm.$options.props; // wtf flow?
         props[key] = validateProp(key, propOptions, propsData, vm);
       }
       toggleObserving(true);
       // keep a copy of raw propsData
       vm.$options.propsData = propsData;
     }
 
     // update listeners
     listeners = listeners || emptyObject;
     var oldListeners = vm.$options._parentListeners;
     vm.$options._parentListeners = listeners;
     updateComponentListeners(vm, listeners, oldListeners);
 
     // resolve slots + force update if has children
     if (needsForceUpdate) {
       vm.$slots = resolveSlots(renderChildren, parentVnode.context);
       vm.$forceUpdate();
     }
 
     {
       isUpdatingChildComponent = false;
     }
   }
 
   function isInInactiveTree (vm) {
     while (vm && (vm = vm.$parent)) {
       if (vm._inactive) { return true }
     }
     return false
   }
 
   function activateChildComponent (vm, direct) {
     if (direct) {
       vm._directInactive = false;
       if (isInInactiveTree(vm)) {
         return
       }
     } else if (vm._directInactive) {
       return
     }
     if (vm._inactive || vm._inactive === null) {
       vm._inactive = false;
       for (var i = 0; i < vm.$children.length; i++) {
         activateChildComponent(vm.$children[i]);
       }
       callHook(vm, 'activated');
     }
   }
 
   function deactivateChildComponent (vm, direct) {
     if (direct) {
       vm._directInactive = true;
       if (isInInactiveTree(vm)) {
         return
       }
     }
     if (!vm._inactive) {
       vm._inactive = true;
       for (var i = 0; i < vm.$children.length; i++) {
         deactivateChildComponent(vm.$children[i]);
       }
       callHook(vm, 'deactivated');
     }
   }
 
   function callHook (vm, hook) {
     // #7573 disable dep collection when invoking lifecycle hooks
     pushTarget();
     var handlers = vm.$options[hook];
     var info = hook + " hook";
     if (handlers) {
       for (var i = 0, j = handlers.length; i < j; i++) {
         invokeWithErrorHandling(handlers[i], vm, null, vm, info);
       }
     }
     if (vm._hasHookEvent) {
       vm.$emit('hook:' + hook);
     }
     popTarget();
   }
 
   /*  */
 
   var MAX_UPDATE_COUNT = 100;
 
   var queue = [];
   var activatedChildren = [];
   var has = {};
   var circular = {};
   var waiting = false;
   var flushing = false;
   var index = 0;
 
   /**
    * Reset the scheduler's state.
    */
   function resetSchedulerState () {
     index = queue.length = activatedChildren.length = 0;
     has = {};
     {
       circular = {};
     }
     waiting = flushing = false;
   }
 
   // Async edge case #6566 requires saving the timestamp when event listeners are
   // attached. However, calling performance.now() has a perf overhead especially
   // if the page has thousands of event listeners. Instead, we take a timestamp
   // every time the scheduler flushes and use that for all event listeners
   // attached during that flush.
   var currentFlushTimestamp = 0;
 
   // Async edge case fix requires storing an event listener's attach timestamp.
   var getNow = Date.now;
 
   // Determine what event timestamp the browser is using. Annoyingly, the
   // timestamp can either be hi-res (relative to page load) or low-res
   // (relative to UNIX epoch), so in order to compare time we have to use the
   // same timestamp type when saving the flush timestamp.
   // All IE versions use low-res event timestamps, and have problematic clock
   // implementations (#9632)
   if (inBrowser && !isIE) {
     var performance = window.performance;
     if (
       performance &&
       typeof performance.now === 'function' &&
       getNow() > document.createEvent('Event').timeStamp
     ) {
       // if the event timestamp, although evaluated AFTER the Date.now(), is
       // smaller than it, it means the event is using a hi-res timestamp,
       // and we need to use the hi-res version for event listener timestamps as
       // well.
       getNow = function () { return performance.now(); };
     }
   }
 
   /**
    * Flush both queues and run the watchers.
    */
   function flushSchedulerQueue () {
     currentFlushTimestamp = getNow();
     flushing = true;
     var watcher, id;
 
     // Sort queue before flush.
     // This ensures that:
     // 1. Components are updated from parent to child. (because parent is always
     //    created before the child)
     // 2. A component's user watchers are run before its render watcher (because
     //    user watchers are created before the render watcher)
     // 3. If a component is destroyed during a parent component's watcher run,
     //    its watchers can be skipped.
     queue.sort(function (a, b) { return a.id - b.id; });
 
     // do not cache length because more watchers might be pushed
     // as we run existing watchers
     for (index = 0; index < queue.length; index++) {
       watcher = queue[index];
       if (watcher.before) {
         watcher.before();
       }
       id = watcher.id;
       has[id] = null;
       watcher.run();
       // in dev build, check and stop circular updates.
       if (has[id] != null) {
         circular[id] = (circular[id] || 0) + 1;
         if (circular[id] > MAX_UPDATE_COUNT) {
           warn(
             'You may have an infinite update loop ' + (
               watcher.user
                 ? ("in watcher with expression \"" + (watcher.expression) + "\"")
                 : "in a component render function."
             ),
             watcher.vm
           );
           break
         }
       }
     }
 
     // keep copies of post queues before resetting state
     var activatedQueue = activatedChildren.slice();
     var updatedQueue = queue.slice();
 
     resetSchedulerState();
 
     // call component updated and activated hooks
     callActivatedHooks(activatedQueue);
     callUpdatedHooks(updatedQueue);
 
     // devtool hook
     /* istanbul ignore if */
     if (devtools && config.devtools) {
       devtools.emit('flush');
     }
   }
 
   function callUpdatedHooks (queue) {
     var i = queue.length;
     while (i--) {
       var watcher = queue[i];
       var vm = watcher.vm;
       if (vm._watcher === watcher && vm._isMounted && !vm._isDestroyed) {
         callHook(vm, 'updated');
       }
     }
   }
 
   /**
    * Queue a kept-alive component that was activated during patch.
    * The queue will be processed after the entire tree has been patched.
    */
   function queueActivatedComponent (vm) {
     // setting _inactive to false here so that a render function can
     // rely on checking whether it's in an inactive tree (e.g. router-view)
     vm._inactive = false;
     activatedChildren.push(vm);
   }
 
   function callActivatedHooks (queue) {
     for (var i = 0; i < queue.length; i++) {
       queue[i]._inactive = true;
       activateChildComponent(queue[i], true /* true */);
     }
   }
 
   /**
    * Push a watcher into the watcher queue.
    * Jobs with duplicate IDs will be skipped unless it's
    * pushed when the queue is being flushed.
    */
   function queueWatcher (watcher) {
     var id = watcher.id;
     if (has[id] == null) {
       has[id] = true;
       if (!flushing) {
         queue.push(watcher);
       } else {
         // if already flushing, splice the watcher based on its id
         // if already past its id, it will be run next immediately.
         var i = queue.length - 1;
         while (i > index && queue[i].id > watcher.id) {
           i--;
         }
         queue.splice(i + 1, 0, watcher);
       }
       // queue the flush
       if (!waiting) {
         waiting = true;
 
         if (!config.async) {
           flushSchedulerQueue();
           return
         }
         nextTick(flushSchedulerQueue);
       }
     }
   }
 
   /*  */
 
 
 
   var uid$2 = 0;
 
   /**
    * A watcher parses an expression, collects dependencies,
    * and fires callback when the expression value changes.
    * This is used for both the $watch() api and directives.
    */
   var Watcher = function Watcher (
     vm,
     expOrFn,
     cb,
     options,
     isRenderWatcher
   ) {
     this.vm = vm;
     if (isRenderWatcher) {
       vm._watcher = this;
     }
     vm._watchers.push(this);
     // options
     if (options) {
       this.deep = !!options.deep;
       this.user = !!options.user;
       this.lazy = !!options.lazy;
       this.sync = !!options.sync;
       this.before = options.before;
     } else {
       this.deep = this.user = this.lazy = this.sync = false;
     }
     this.cb = cb;
     this.id = ++uid$2; // uid for batching
     this.active = true;
     this.dirty = this.lazy; // for lazy watchers
     this.deps = [];
     this.newDeps = [];
     this.depIds = new _Set();
     this.newDepIds = new _Set();
     this.expression = expOrFn.toString();
     // parse expression for getter
     if (typeof expOrFn === 'function') {
       this.getter = expOrFn;
     } else {
       this.getter = parsePath(expOrFn);
       if (!this.getter) {
         this.getter = noop;
         warn(
           "Failed watching path: \"" + expOrFn + "\" " +
           'Watcher only accepts simple dot-delimited paths. ' +
           'For full control, use a function instead.',
           vm
         );
       }
     }
     this.value = this.lazy
       ? undefined
       : this.get();
   };
 
   /**
    * Evaluate the getter, and re-collect dependencies.
    */
   Watcher.prototype.get = function get () {
     pushTarget(this);
     var value;
     var vm = this.vm;
     try {
       value = this.getter.call(vm, vm);
     } catch (e) {
       if (this.user) {
         handleError(e, vm, ("getter for watcher \"" + (this.expression) + "\""));
       } else {
         throw e
       }
     } finally {
       // "touch" every property so they are all tracked as
       // dependencies for deep watching
       if (this.deep) {
         traverse(value);
       }
       popTarget();
       this.cleanupDeps();
     }
     return value
   };
 
   /**
    * Add a dependency to this directive.
    */
   Watcher.prototype.addDep = function addDep (dep) {
     var id = dep.id;
     if (!this.newDepIds.has(id)) {
       this.newDepIds.add(id);
       this.newDeps.push(dep);
       if (!this.depIds.has(id)) {
         dep.addSub(this);
       }
     }
   };
 
   /**
    * Clean up for dependency collection.
    */
   Watcher.prototype.cleanupDeps = function cleanupDeps () {
     var i = this.deps.length;
     while (i--) {
       var dep = this.deps[i];
       if (!this.newDepIds.has(dep.id)) {
         dep.removeSub(this);
       }
     }
     var tmp = this.depIds;
     this.depIds = this.newDepIds;
     this.newDepIds = tmp;
     this.newDepIds.clear();
     tmp = this.deps;
     this.deps = this.newDeps;
     this.newDeps = tmp;
     this.newDeps.length = 0;
   };
 
   /**
    * Subscriber interface.
    * Will be called when a dependency changes.
    */
   Watcher.prototype.update = function update () {
     /* istanbul ignore else */
     if (this.lazy) {
       this.dirty = true;
     } else if (this.sync) {
       this.run();
     } else {
       queueWatcher(this);
     }
   };
 
   /**
    * Scheduler job interface.
    * Will be called by the scheduler.
    */
   Watcher.prototype.run = function run () {
     if (this.active) {
       var value = this.get();
       if (
         value !== this.value ||
         // Deep watchers and watchers on Object/Arrays should fire even
         // when the value is the same, because the value may
         // have mutated.
         isObject(value) ||
         this.deep
       ) {
         // set new value
         var oldValue = this.value;
         this.value = value;
         if (this.user) {
           try {
             this.cb.call(this.vm, value, oldValue);
           } catch (e) {
             handleError(e, this.vm, ("callback for watcher \"" + (this.expression) + "\""));
           }
         } else {
           this.cb.call(this.vm, value, oldValue);
         }
       }
     }
   };
 
   /**
    * Evaluate the value of the watcher.
    * This only gets called for lazy watchers.
    */
   Watcher.prototype.evaluate = function evaluate () {
     this.value = this.get();
     this.dirty = false;
   };
 
   /**
    * Depend on all deps collected by this watcher.
    */
   Watcher.prototype.depend = function depend () {
     var i = this.deps.length;
     while (i--) {
       this.deps[i].depend();
     }
   };
 
   /**
    * Remove self from all dependencies' subscriber list.
    */
   Watcher.prototype.teardown = function teardown () {
     if (this.active) {
       // remove self from vm's watcher list
       // this is a somewhat expensive operation so we skip it
       // if the vm is being destroyed.
       if (!this.vm._isBeingDestroyed) {
         remove(this.vm._watchers, this);
       }
       var i = this.deps.length;
       while (i--) {
         this.deps[i].removeSub(this);
       }
       this.active = false;
     }
   };
 
   /*  */
 
   var sharedPropertyDefinition = {
     enumerable: true,
     configurable: true,
     get: noop,
     set: noop
   };
 
   function proxy (target, sourceKey, key) {
     sharedPropertyDefinition.get = function proxyGetter () {
       return this[sourceKey][key]
     };
     sharedPropertyDefinition.set = function proxySetter (val) {
       this[sourceKey][key] = val;
     };
     Object.defineProperty(target, key, sharedPropertyDefinition);
   }
 
   function initState (vm) {
     vm._watchers = [];
     var opts = vm.$options;
     if (opts.props) { initProps(vm, opts.props); }
     if (opts.methods) { initMethods(vm, opts.methods); }
     if (opts.data) {
       initData(vm);
     } else {
       observe(vm._data = {}, true /* asRootData */);
     }
     if (opts.computed) { initComputed(vm, opts.computed); }
     if (opts.watch && opts.watch !== nativeWatch) {
       initWatch(vm, opts.watch);
     }
   }
 
   function initProps (vm, propsOptions) {
     var propsData = vm.$options.propsData || {};
     var props = vm._props = {};
     // cache prop keys so that future props updates can iterate using Array
     // instead of dynamic object key enumeration.
     var keys = vm.$options._propKeys = [];
     var isRoot = !vm.$parent;
     // root instance props should be converted
     if (!isRoot) {
       toggleObserving(false);
     }
     var loop = function ( key ) {
       keys.push(key);
       var value = validateProp(key, propsOptions, propsData, vm);
       /* istanbul ignore else */
       {
         var hyphenatedKey = hyphenate(key);
         if (isReservedAttribute(hyphenatedKey) ||
             config.isReservedAttr(hyphenatedKey)) {
           warn(
             ("\"" + hyphenatedKey + "\" is a reserved attribute and cannot be used as component prop."),
             vm
           );
         }
         defineReactive$$1(props, key, value, function () {
           if (!isRoot && !isUpdatingChildComponent) {
             warn(
               "Avoid mutating a prop directly since the value will be " +
               "overwritten whenever the parent component re-renders. " +
               "Instead, use a data or computed property based on the prop's " +
               "value. Prop being mutated: \"" + key + "\"",
               vm
             );
           }
         });
       }
       // static props are already proxied on the component's prototype
       // during Vue.extend(). We only need to proxy props defined at
       // instantiation here.
       if (!(key in vm)) {
         proxy(vm, "_props", key);
       }
     };
 
     for (var key in propsOptions) loop( key );
     toggleObserving(true);
   }
 
   function initData (vm) {
     var data = vm.$options.data;
     data = vm._data = typeof data === 'function'
       ? getData(data, vm)
       : data || {};
     if (!isPlainObject(data)) {
       data = {};
       warn(
         'data functions should return an object:\n' +
         'https://vuejs.org/v2/guide/components.html#data-Must-Be-a-Function',
         vm
       );
     }
     // proxy data on instance
     var keys = Object.keys(data);
     var props = vm.$options.props;
     var methods = vm.$options.methods;
     var i = keys.length;
     while (i--) {
       var key = keys[i];
       {
         if (methods && hasOwn(methods, key)) {
           warn(
             ("Method \"" + key + "\" has already been defined as a data property."),
             vm
           );
         }
       }
       if (props && hasOwn(props, key)) {
         warn(
           "The data property \"" + key + "\" is already declared as a prop. " +
           "Use prop default value instead.",
           vm
         );
       } else if (!isReserved(key)) {
         proxy(vm, "_data", key);
       }
     }
     // observe data
     observe(data, true /* asRootData */);
   }
 
   function getData (data, vm) {
     // #7573 disable dep collection when invoking data getters
     pushTarget();
     try {
       return data.call(vm, vm)
     } catch (e) {
       handleError(e, vm, "data()");
       return {}
     } finally {
       popTarget();
     }
   }
 
   var computedWatcherOptions = { lazy: true };
 
   function initComputed (vm, computed) {
     // $flow-disable-line
     var watchers = vm._computedWatchers = Object.create(null);
     // computed properties are just getters during SSR
     var isSSR = isServerRendering();
 
     for (var key in computed) {
       var userDef = computed[key];
       var getter = typeof userDef === 'function' ? userDef : userDef.get;
       if (getter == null) {
         warn(
           ("Getter is missing for computed property \"" + key + "\"."),
           vm
         );
       }
 
       if (!isSSR) {
         // create internal watcher for the computed property.
         watchers[key] = new Watcher(
           vm,
           getter || noop,
           noop,
           computedWatcherOptions
         );
       }
 
       // component-defined computed properties are already defined on the
       // component prototype. We only need to define computed properties defined
       // at instantiation here.
       if (!(key in vm)) {
         defineComputed(vm, key, userDef);
       } else {
         if (key in vm.$data) {
           warn(("The computed property \"" + key + "\" is already defined in data."), vm);
         } else if (vm.$options.props && key in vm.$options.props) {
           warn(("The computed property \"" + key + "\" is already defined as a prop."), vm);
         }
       }
     }
   }
 
   function defineComputed (
     target,
     key,
     userDef
   ) {
     var shouldCache = !isServerRendering();
     if (typeof userDef === 'function') {
       sharedPropertyDefinition.get = shouldCache
         ? createComputedGetter(key)
         : createGetterInvoker(userDef);
       sharedPropertyDefinition.set = noop;
     } else {
       sharedPropertyDefinition.get = userDef.get
         ? shouldCache && userDef.cache !== false
           ? createComputedGetter(key)
           : createGetterInvoker(userDef.get)
         : noop;
       sharedPropertyDefinition.set = userDef.set || noop;
     }
     if (sharedPropertyDefinition.set === noop) {
       sharedPropertyDefinition.set = function () {
         warn(
           ("Computed property \"" + key + "\" was assigned to but it has no setter."),
           this
         );
       };
     }
     Object.defineProperty(target, key, sharedPropertyDefinition);
   }
 
   function createComputedGetter (key) {
     return function computedGetter () {
       var watcher = this._computedWatchers && this._computedWatchers[key];
       if (watcher) {
         if (watcher.dirty) {
           watcher.evaluate();
         }
         if (Dep.target) {
           watcher.depend();
         }
         return watcher.value
       }
     }
   }
 
   function createGetterInvoker(fn) {
     return function computedGetter () {
       return fn.call(this, this)
     }
   }
 
   function initMethods (vm, methods) {
     var props = vm.$options.props;
     for (var key in methods) {
       {
         if (typeof methods[key] !== 'function') {
           warn(
             "Method \"" + key + "\" has type \"" + (typeof methods[key]) + "\" in the component definition. " +
             "Did you reference the function correctly?",
             vm
           );
         }
         if (props && hasOwn(props, key)) {
           warn(
             ("Method \"" + key + "\" has already been defined as a prop."),
             vm
           );
         }
         if ((key in vm) && isReserved(key)) {
           warn(
             "Method \"" + key + "\" conflicts with an existing Vue instance method. " +
             "Avoid defining component methods that start with _ or $."
           );
         }
       }
       vm[key] = typeof methods[key] !== 'function' ? noop : bind(methods[key], vm);
     }
   }
 
   function initWatch (vm, watch) {
     for (var key in watch) {
       var handler = watch[key];
       if (Array.isArray(handler)) {
         for (var i = 0; i < handler.length; i++) {
           createWatcher(vm, key, handler[i]);
         }
       } else {
         createWatcher(vm, key, handler);
       }
     }
   }
 
   function createWatcher (
     vm,
     expOrFn,
     handler,
     options
   ) {
     if (isPlainObject(handler)) {
       options = handler;
       handler = handler.handler;
     }
     if (typeof handler === 'string') {
       handler = vm[handler];
     }
     return vm.$watch(expOrFn, handler, options)
   }
 
   function stateMixin (Vue) {
     // flow somehow has problems with directly declared definition object
     // when using Object.defineProperty, so we have to procedurally build up
     // the object here.
     var dataDef = {};
     dataDef.get = function () { return this._data };
     var propsDef = {};
     propsDef.get = function () { return this._props };
     {
       dataDef.set = function () {
         warn(
           'Avoid replacing instance root $data. ' +
           'Use nested data properties instead.',
           this
         );
       };
       propsDef.set = function () {
         warn("$props is readonly.", this);
       };
     }
     Object.defineProperty(Vue.prototype, '$data', dataDef);
     Object.defineProperty(Vue.prototype, '$props', propsDef);
 
     Vue.prototype.$set = set;
     Vue.prototype.$delete = del;
 
     Vue.prototype.$watch = function (
       expOrFn,
       cb,
       options
     ) {
       var vm = this;
       if (isPlainObject(cb)) {
         return createWatcher(vm, expOrFn, cb, options)
       }
       options = options || {};
       options.user = true;
       var watcher = new Watcher(vm, expOrFn, cb, options);
       if (options.immediate) {
         try {
           cb.call(vm, watcher.value);
         } catch (error) {
           handleError(error, vm, ("callback for immediate watcher \"" + (watcher.expression) + "\""));
         }
       }
       return function unwatchFn () {
         watcher.teardown();
       }
     };
   }
 
   /*  */
 
   var uid$3 = 0;
 
   function initMixin (Vue) {
     Vue.prototype._init = function (options) {
       var vm = this;
       // a uid
       vm._uid = uid$3++;
 
       var startTag, endTag;
       /* istanbul ignore if */
       if (config.performance && mark) {
         startTag = "vue-perf-start:" + (vm._uid);
         endTag = "vue-perf-end:" + (vm._uid);
         mark(startTag);
       }
 
       // a flag to avoid this being observed
       vm._isVue = true;
       // merge options
       if (options && options._isComponent) {
         // optimize internal component instantiation
         // since dynamic options merging is pretty slow, and none of the
         // internal component options needs special treatment.
         initInternalComponent(vm, options);
       } else {
         vm.$options = mergeOptions(
           resolveConstructorOptions(vm.constructor),
           options || {},
           vm
         );
       }
       /* istanbul ignore else */
       {
         initProxy(vm);
       }
       // expose real self
       vm._self = vm;
       initLifecycle(vm);
       initEvents(vm);
       initRender(vm);
       callHook(vm, 'beforeCreate');
       initInjections(vm); // resolve injections before data/props
       initState(vm);
       initProvide(vm); // resolve provide after data/props
       callHook(vm, 'created');
 
       /* istanbul ignore if */
       if (config.performance && mark) {
         vm._name = formatComponentName(vm, false);
         mark(endTag);
         measure(("vue " + (vm._name) + " init"), startTag, endTag);
       }
 
       if (vm.$options.el) {
         vm.$mount(vm.$options.el);
       }
     };
   }
 
   function initInternalComponent (vm, options) {
     var opts = vm.$options = Object.create(vm.constructor.options);
     // doing this because it's faster than dynamic enumeration.
     var parentVnode = options._parentVnode;
     opts.parent = options.parent;
     opts._parentVnode = parentVnode;
 
     var vnodeComponentOptions = parentVnode.componentOptions;
     opts.propsData = vnodeComponentOptions.propsData;
     opts._parentListeners = vnodeComponentOptions.listeners;
     opts._renderChildren = vnodeComponentOptions.children;
     opts._componentTag = vnodeComponentOptions.tag;
 
     if (options.render) {
       opts.render = options.render;
       opts.staticRenderFns = options.staticRenderFns;
     }
   }
 
   function resolveConstructorOptions (Ctor) {
     var options = Ctor.options;
     if (Ctor.super) {
       var superOptions = resolveConstructorOptions(Ctor.super);
       var cachedSuperOptions = Ctor.superOptions;
       if (superOptions !== cachedSuperOptions) {
         // super option changed,
         // need to resolve new options.
         Ctor.superOptions = superOptions;
         // check if there are any late-modified/attached options (#4976)
         var modifiedOptions = resolveModifiedOptions(Ctor);
         // update base extend options
         if (modifiedOptions) {
           extend(Ctor.extendOptions, modifiedOptions);
         }
         options = Ctor.options = mergeOptions(superOptions, Ctor.extendOptions);
         if (options.name) {
           options.components[options.name] = Ctor;
         }
       }
     }
     return options
   }
 
   function resolveModifiedOptions (Ctor) {
     var modified;
     var latest = Ctor.options;
     var sealed = Ctor.sealedOptions;
     for (var key in latest) {
       if (latest[key] !== sealed[key]) {
         if (!modified) { modified = {}; }
         modified[key] = latest[key];
       }
     }
     return modified
   }
 
   function Vue (options) {
     if (!(this instanceof Vue)
     ) {
       warn('Vue is a constructor and should be called with the `new` keyword');
     }
     this._init(options);
   }
 
   initMixin(Vue);
   stateMixin(Vue);
   eventsMixin(Vue);
   lifecycleMixin(Vue);
   renderMixin(Vue);
 
   /*  */
 
   function initUse (Vue) {
     Vue.use = function (plugin) {
       var installedPlugins = (this._installedPlugins || (this._installedPlugins = []));
       if (installedPlugins.indexOf(plugin) > -1) {
         return this
       }
 
       // additional parameters
       var args = toArray(arguments, 1);
       args.unshift(this);
       if (typeof plugin.install === 'function') {
         plugin.install.apply(plugin, args);
       } else if (typeof plugin === 'function') {
         plugin.apply(null, args);
       }
       installedPlugins.push(plugin);
       return this
     };
   }
 
   /*  */
 
   function initMixin$1 (Vue) {
     Vue.mixin = function (mixin) {
       this.options = mergeOptions(this.options, mixin);
       return this
     };
   }
 
   /*  */
 
   function initExtend (Vue) {
     /**
      * Each instance constructor, including Vue, has a unique
      * cid. This enables us to create wrapped "child
      * constructors" for prototypal inheritance and cache them.
      */
     Vue.cid = 0;
     var cid = 1;
 
     /**
      * Class inheritance
      */
     Vue.extend = function (extendOptions) {
       extendOptions = extendOptions || {};
       var Super = this;
       var SuperId = Super.cid;
       var cachedCtors = extendOptions._Ctor || (extendOptions._Ctor = {});
       if (cachedCtors[SuperId]) {
         return cachedCtors[SuperId]
       }
 
       var name = extendOptions.name || Super.options.name;
       if (name) {
         validateComponentName(name);
       }
 
       var Sub = function VueComponent (options) {
         this._init(options);
       };
       Sub.prototype = Object.create(Super.prototype);
       Sub.prototype.constructor = Sub;
       Sub.cid = cid++;
       Sub.options = mergeOptions(
         Super.options,
         extendOptions
       );
       Sub['super'] = Super;
 
       // For props and computed properties, we define the proxy getters on
       // the Vue instances at extension time, on the extended prototype. This
       // avoids Object.defineProperty calls for each instance created.
       if (Sub.options.props) {
         initProps$1(Sub);
       }
       if (Sub.options.computed) {
         initComputed$1(Sub);
       }
 
       // allow further extension/mixin/plugin usage
       Sub.extend = Super.extend;
       Sub.mixin = Super.mixin;
       Sub.use = Super.use;
 
       // create asset registers, so extended classes
       // can have their private assets too.
       ASSET_TYPES.forEach(function (type) {
         Sub[type] = Super[type];
       });
       // enable recursive self-lookup
       if (name) {
         Sub.options.components[name] = Sub;
       }
 
       // keep a reference to the super options at extension time.
       // later at instantiation we can check if Super's options have
       // been updated.
       Sub.superOptions = Super.options;
       Sub.extendOptions = extendOptions;
       Sub.sealedOptions = extend({}, Sub.options);
 
       // cache constructor
       cachedCtors[SuperId] = Sub;
       return Sub
     };
   }
 
   function initProps$1 (Comp) {
     var props = Comp.options.props;
     for (var key in props) {
       proxy(Comp.prototype, "_props", key);
     }
   }
 
   function initComputed$1 (Comp) {
     var computed = Comp.options.computed;
     for (var key in computed) {
       defineComputed(Comp.prototype, key, computed[key]);
     }
   }
 
   /*  */
 
   function initAssetRegisters (Vue) {
     /**
      * Create asset registration methods.
      */
     ASSET_TYPES.forEach(function (type) {
       Vue[type] = function (
         id,
         definition
       ) {
         if (!definition) {
           return this.options[type + 's'][id]
         } else {
           /* istanbul ignore if */
           if (type === 'component') {
             validateComponentName(id);
           }
           if (type === 'component' && isPlainObject(definition)) {
             definition.name = definition.name || id;
             definition = this.options._base.extend(definition);
           }
           if (type === 'directive' && typeof definition === 'function') {
             definition = { bind: definition, update: definition };
           }
           this.options[type + 's'][id] = definition;
           return definition
         }
       };
     });
   }
 
   /*  */
 
 
 
   function getComponentName (opts) {
     return opts && (opts.Ctor.options.name || opts.tag)
   }
 
   function matches (pattern, name) {
     if (Array.isArray(pattern)) {
       return pattern.indexOf(name) > -1
     } else if (typeof pattern === 'string') {
       return pattern.split(',').indexOf(name) > -1
     } else if (isRegExp(pattern)) {
       return pattern.test(name)
     }
     /* istanbul ignore next */
     return false
   }
 
   function pruneCache (keepAliveInstance, filter) {
     var cache = keepAliveInstance.cache;
     var keys = keepAliveInstance.keys;
     var _vnode = keepAliveInstance._vnode;
     for (var key in cache) {
       var cachedNode = cache[key];
       if (cachedNode) {
         var name = getComponentName(cachedNode.componentOptions);
         if (name && !filter(name)) {
           pruneCacheEntry(cache, key, keys, _vnode);
         }
       }
     }
   }
 
   function pruneCacheEntry (
     cache,
     key,
     keys,
     current
   ) {
     var cached$$1 = cache[key];
     if (cached$$1 && (!current || cached$$1.tag !== current.tag)) {
       cached$$1.componentInstance.$destroy();
     }
     cache[key] = null;
     remove(keys, key);
   }
 
   var patternTypes = [String, RegExp, Array];
 
   var KeepAlive = {
     name: 'keep-alive',
     abstract: true,
 
     props: {
       include: patternTypes,
       exclude: patternTypes,
       max: [String, Number]
     },
 
     created: function created () {
       this.cache = Object.create(null);
       this.keys = [];
     },
 
     destroyed: function destroyed () {
       for (var key in this.cache) {
         pruneCacheEntry(this.cache, key, this.keys);
       }
     },
 
     mounted: function mounted () {
       var this$1 = this;
 
       this.$watch('include', function (val) {
         pruneCache(this$1, function (name) { return matches(val, name); });
       });
       this.$watch('exclude', function (val) {
         pruneCache(this$1, function (name) { return !matches(val, name); });
       });
     },
 
     render: function render () {
       var slot = this.$slots.default;
       var vnode = getFirstComponentChild(slot);
       var componentOptions = vnode && vnode.componentOptions;
       if (componentOptions) {
         // check pattern
         var name = getComponentName(componentOptions);
         var ref = this;
         var include = ref.include;
         var exclude = ref.exclude;
         if (
           // not included
           (include && (!name || !matches(include, name))) ||
           // excluded
           (exclude && name && matches(exclude, name))
         ) {
           return vnode
         }
 
         var ref$1 = this;
         var cache = ref$1.cache;
         var keys = ref$1.keys;
         var key = vnode.key == null
           // same constructor may get registered as different local components
           // so cid alone is not enough (#3269)
           ? componentOptions.Ctor.cid + (componentOptions.tag ? ("::" + (componentOptions.tag)) : '')
           : vnode.key;
         if (cache[key]) {
           vnode.componentInstance = cache[key].componentInstance;
           // make current key freshest
           remove(keys, key);
           keys.push(key);
         } else {
           cache[key] = vnode;
           keys.push(key);
           // prune oldest entry
           if (this.max && keys.length > parseInt(this.max)) {
             pruneCacheEntry(cache, keys[0], keys, this._vnode);
           }
         }
 
         vnode.data.keepAlive = true;
       }
       return vnode || (slot && slot[0])
     }
   };
 
   var builtInComponents = {
     KeepAlive: KeepAlive
   };
 
   /*  */
 
   function initGlobalAPI (Vue) {
     // config
     var configDef = {};
     configDef.get = function () { return config; };
     {
       configDef.set = function () {
         warn(
           'Do not replace the Vue.config object, set individual fields instead.'
         );
       };
     }
     Object.defineProperty(Vue, 'config', configDef);
 
     // exposed util methods.
     // NOTE: these are not considered part of the public API - avoid relying on
     // them unless you are aware of the risk.
     Vue.util = {
       warn: warn,
       extend: extend,
       mergeOptions: mergeOptions,
       defineReactive: defineReactive$$1
     };
 
     Vue.set = set;
     Vue.delete = del;
     Vue.nextTick = nextTick;
 
     // 2.6 explicit observable API
     Vue.observable = function (obj) {
       observe(obj);
       return obj
     };
 
     Vue.options = Object.create(null);
     ASSET_TYPES.forEach(function (type) {
       Vue.options[type + 's'] = Object.create(null);
     });
 
     // this is used to identify the "base" constructor to extend all plain-object
     // components with in Weex's multi-instance scenarios.
     Vue.options._base = Vue;
 
     extend(Vue.options.components, builtInComponents);
 
     initUse(Vue);
     initMixin$1(Vue);
     initExtend(Vue);
     initAssetRegisters(Vue);
   }
 
   initGlobalAPI(Vue);
 
   Object.defineProperty(Vue.prototype, '$isServer', {
     get: isServerRendering
   });
 
   Object.defineProperty(Vue.prototype, '$ssrContext', {
     get: function get () {
       /* istanbul ignore next */
       return this.$vnode && this.$vnode.ssrContext
     }
   });
 
   // expose FunctionalRenderContext for ssr runtime helper installation
   Object.defineProperty(Vue, 'FunctionalRenderContext', {
     value: FunctionalRenderContext
   });
 
   Vue.version = '2.6.12';
 
   /*  */
 
   // these are reserved for web because they are directly compiled away
   // during template compilation
   var isReservedAttr = makeMap('style,class');
 
   // attributes that should be using props for binding
   var acceptValue = makeMap('input,textarea,option,select,progress');
   var mustUseProp = function (tag, type, attr) {
     return (
       (attr === 'value' && acceptValue(tag)) && type !== 'button' ||
       (attr === 'selected' && tag === 'option') ||
       (attr === 'checked' && tag === 'input') ||
       (attr === 'muted' && tag === 'video')
     )
   };
 
   var isEnumeratedAttr = makeMap('contenteditable,draggable,spellcheck');
 
   var isValidContentEditableValue = makeMap('events,caret,typing,plaintext-only');
 
   var convertEnumeratedValue = function (key, value) {
     return isFalsyAttrValue(value) || value === 'false'
       ? 'false'
       // allow arbitrary string value for contenteditable
       : key === 'contenteditable' && isValidContentEditableValue(value)
         ? value
         : 'true'
   };
 
   var isBooleanAttr = makeMap(
     'allowfullscreen,async,autofocus,autoplay,checked,compact,controls,declare,' +
     'default,defaultchecked,defaultmuted,defaultselected,defer,disabled,' +
     'enabled,formnovalidate,hidden,indeterminate,inert,ismap,itemscope,loop,multiple,' +
     'muted,nohref,noresize,noshade,novalidate,nowrap,open,pauseonexit,readonly,' +
     'required,reversed,scoped,seamless,selected,sortable,translate,' +
     'truespeed,typemustmatch,visible'
   );
 
   var xlinkNS = 'http://www.w3.org/1999/xlink';
 
   var isXlink = function (name) {
     return name.charAt(5) === ':' && name.slice(0, 5) === 'xlink'
   };
 
   var getXlinkProp = function (name) {
     return isXlink(name) ? name.slice(6, name.length) : ''
   };
 
   var isFalsyAttrValue = function (val) {
     return val == null || val === false
   };
 
   /*  */
 
   function genClassForVnode (vnode) {
     var data = vnode.data;
     var parentNode = vnode;
     var childNode = vnode;
     while (isDef(childNode.componentInstance)) {
       childNode = childNode.componentInstance._vnode;
       if (childNode && childNode.data) {
         data = mergeClassData(childNode.data, data);
       }
     }
     while (isDef(parentNode = parentNode.parent)) {
       if (parentNode && parentNode.data) {
         data = mergeClassData(data, parentNode.data);
       }
     }
     return renderClass(data.staticClass, data.class)
   }
 
   function mergeClassData (child, parent) {
     return {
       staticClass: concat(child.staticClass, parent.staticClass),
       class: isDef(child.class)
         ? [child.class, parent.class]
         : parent.class
     }
   }
 
   function renderClass (
     staticClass,
     dynamicClass
   ) {
     if (isDef(staticClass) || isDef(dynamicClass)) {
       return concat(staticClass, stringifyClass(dynamicClass))
     }
     /* istanbul ignore next */
     return ''
   }
 
   function concat (a, b) {
     return a ? b ? (a + ' ' + b) : a : (b || '')
   }
 
   function stringifyClass (value) {
     if (Array.isArray(value)) {
       return stringifyArray(value)
     }
     if (isObject(value)) {
       return stringifyObject(value)
     }
     if (typeof value === 'string') {
       return value
     }
     /* istanbul ignore next */
     return ''
   }
 
   function stringifyArray (value) {
     var res = '';
     var stringified;
     for (var i = 0, l = value.length; i < l; i++) {
       if (isDef(stringified = stringifyClass(value[i])) && stringified !== '') {
         if (res) { res += ' '; }
         res += stringified;
       }
     }
     return res
   }
 
   function stringifyObject (value) {
     var res = '';
     for (var key in value) {
       if (value[key]) {
         if (res) { res += ' '; }
         res += key;
       }
     }
     return res
   }
 
   /*  */
 
   var namespaceMap = {
     svg: 'http://www.w3.org/2000/svg',
     math: 'http://www.w3.org/1998/Math/MathML'
   };
 
   var isHTMLTag = makeMap(
     'html,body,base,head,link,meta,style,title,' +
     'address,article,aside,footer,header,h1,h2,h3,h4,h5,h6,hgroup,nav,section,' +
     'div,dd,dl,dt,figcaption,figure,picture,hr,img,li,main,ol,p,pre,ul,' +
     'a,b,abbr,bdi,bdo,br,cite,code,data,dfn,em,i,kbd,mark,q,rp,rt,rtc,ruby,' +
     's,samp,small,span,strong,sub,sup,time,u,var,wbr,area,audio,map,track,video,' +
     'embed,object,param,source,canvas,script,noscript,del,ins,' +
     'caption,col,colgroup,table,thead,tbody,td,th,tr,' +
     'button,datalist,fieldset,form,input,label,legend,meter,optgroup,option,' +
     'output,progress,select,textarea,' +
     'details,dialog,menu,menuitem,summary,' +
     'content,element,shadow,template,blockquote,iframe,tfoot'
   );
 
   // this map is intentionally selective, only covering SVG elements that may
   // contain child elements.
   var isSVG = makeMap(
     'svg,animate,circle,clippath,cursor,defs,desc,ellipse,filter,font-face,' +
     'foreignObject,g,glyph,image,line,marker,mask,missing-glyph,path,pattern,' +
     'polygon,polyline,rect,switch,symbol,text,textpath,tspan,use,view',
     true
   );
 
   var isPreTag = function (tag) { return tag === 'pre'; };
 
   var isReservedTag = function (tag) {
     return isHTMLTag(tag) || isSVG(tag)
   };
 
   function getTagNamespace (tag) {
     if (isSVG(tag)) {
       return 'svg'
     }
     // basic support for MathML
     // note it doesn't support other MathML elements being component roots
     if (tag === 'math') {
       return 'math'
     }
   }
 
   var unknownElementCache = Object.create(null);
   function isUnknownElement (tag) {
     /* istanbul ignore if */
     if (!inBrowser) {
       return true
     }
     if (isReservedTag(tag)) {
       return false
     }
     tag = tag.toLowerCase();
     /* istanbul ignore if */
     if (unknownElementCache[tag] != null) {
       return unknownElementCache[tag]
     }
     var el = document.createElement(tag);
     if (tag.indexOf('-') > -1) {
       // http://stackoverflow.com/a/28210364/1070244
       return (unknownElementCache[tag] = (
         el.constructor === window.HTMLUnknownElement ||
         el.constructor === window.HTMLElement
       ))
     } else {
       return (unknownElementCache[tag] = /HTMLUnknownElement/.test(el.toString()))
     }
   }
 
   var isTextInputType = makeMap('text,number,password,search,email,tel,url');
 
   /*  */
 
   /**
    * Query an element selector if it's not an element already.
    */
   function query (el) {
     if (typeof el === 'string') {
       var selected = document.querySelector(el);
       if (!selected) {
         warn(
           'Cannot find element: ' + el
         );
         return document.createElement('div')
       }
       return selected
     } else {
       return el
     }
   }
 
   /*  */
 
   function createElement$1 (tagName, vnode) {
     var elm = document.createElement(tagName);
     if (tagName !== 'select') {
       return elm
     }
     // false or null will remove the attribute but undefined will not
     if (vnode.data && vnode.data.attrs && vnode.data.attrs.multiple !== undefined) {
       elm.setAttribute('multiple', 'multiple');
     }
     return elm
   }
 
   function createElementNS (namespace, tagName) {
     return document.createElementNS(namespaceMap[namespace], tagName)
   }
 
   function createTextNode (text) {
     return document.createTextNode(text)
   }
 
   function createComment (text) {
     return document.createComment(text)
   }
 
   function insertBefore (parentNode, newNode, referenceNode) {
     parentNode.insertBefore(newNode, referenceNode);
   }
 
   function removeChild (node, child) {
     node.removeChild(child);
   }
 
   function appendChild (node, child) {
     node.appendChild(child);
   }
 
   function parentNode (node) {
     return node.parentNode
   }
 
   function nextSibling (node) {
     return node.nextSibling
   }
 
   function tagName (node) {
     return node.tagName
   }
 
   function setTextContent (node, text) {
     node.textContent = text;
   }
 
   function setStyleScope (node, scopeId) {
     node.setAttribute(scopeId, '');
   }
 
   var nodeOps = /*#__PURE__*/Object.freeze({
     createElement: createElement$1,
     createElementNS: createElementNS,
     createTextNode: createTextNode,
     createComment: createComment,
     insertBefore: insertBefore,
     removeChild: removeChild,
     appendChild: appendChild,
     parentNode: parentNode,
     nextSibling: nextSibling,
     tagName: tagName,
     setTextContent: setTextContent,
     setStyleScope: setStyleScope
   });
 
   /*  */
 
   var ref = {
     create: function create (_, vnode) {
       registerRef(vnode);
     },
     update: function update (oldVnode, vnode) {
       if (oldVnode.data.ref !== vnode.data.ref) {
         registerRef(oldVnode, true);
         registerRef(vnode);
       }
     },
     destroy: function destroy (vnode) {
       registerRef(vnode, true);
     }
   };
 
   function registerRef (vnode, isRemoval) {
     var key = vnode.data.ref;
     if (!isDef(key)) { return }
 
     var vm = vnode.context;
     var ref = vnode.componentInstance || vnode.elm;
     var refs = vm.$refs;
     if (isRemoval) {
       if (Array.isArray(refs[key])) {
         remove(refs[key], ref);
       } else if (refs[key] === ref) {
         refs[key] = undefined;
       }
     } else {
       if (vnode.data.refInFor) {
         if (!Array.isArray(refs[key])) {
           refs[key] = [ref];
         } else if (refs[key].indexOf(ref) < 0) {
           // $flow-disable-line
           refs[key].push(ref);
         }
       } else {
         refs[key] = ref;
       }
     }
   }
 
   /**
    * Virtual DOM patching algorithm based on Snabbdom by
    * Simon Friis Vindum (@paldepind)
    * Licensed under the MIT License
    * https://github.com/paldepind/snabbdom/blob/master/LICENSE
    *
    * modified by Evan You (@yyx990803)
    *
    * Not type-checking this because this file is perf-critical and the cost
    * of making flow understand it is not worth it.
    */
 
   var emptyNode = new VNode('', {}, []);
 
   var hooks = ['create', 'activate', 'update', 'remove', 'destroy'];
 
   function sameVnode (a, b) {
     return (
       a.key === b.key && (
         (
           a.tag === b.tag &&
           a.isComment === b.isComment &&
           isDef(a.data) === isDef(b.data) &&
           sameInputType(a, b)
         ) || (
           isTrue(a.isAsyncPlaceholder) &&
           a.asyncFactory === b.asyncFactory &&
           isUndef(b.asyncFactory.error)
         )
       )
     )
   }
 
   function sameInputType (a, b) {
     if (a.tag !== 'input') { return true }
     var i;
     var typeA = isDef(i = a.data) && isDef(i = i.attrs) && i.type;
     var typeB = isDef(i = b.data) && isDef(i = i.attrs) && i.type;
     return typeA === typeB || isTextInputType(typeA) && isTextInputType(typeB)
   }
 
   function createKeyToOldIdx (children, beginIdx, endIdx) {
     var i, key;
     var map = {};
     for (i = beginIdx; i <= endIdx; ++i) {
       key = children[i].key;
       if (isDef(key)) { map[key] = i; }
     }
     return map
   }
 
   function createPatchFunction (backend) {
     var i, j;
     var cbs = {};
 
     var modules = backend.modules;
     var nodeOps = backend.nodeOps;
 
     for (i = 0; i < hooks.length; ++i) {
       cbs[hooks[i]] = [];
       for (j = 0; j < modules.length; ++j) {
         if (isDef(modules[j][hooks[i]])) {
           cbs[hooks[i]].push(modules[j][hooks[i]]);
         }
       }
     }
 
     function emptyNodeAt (elm) {
       return new VNode(nodeOps.tagName(elm).toLowerCase(), {}, [], undefined, elm)
     }
 
     function createRmCb (childElm, listeners) {
       function remove$$1 () {
         if (--remove$$1.listeners === 0) {
           removeNode(childElm);
         }
       }
       remove$$1.listeners = listeners;
       return remove$$1
     }
 
     function removeNode (el) {
       var parent = nodeOps.parentNode(el);
       // element may have already been removed due to v-html / v-text
       if (isDef(parent)) {
         nodeOps.removeChild(parent, el);
       }
     }
 
     function isUnknownElement$$1 (vnode, inVPre) {
       return (
         !inVPre &&
         !vnode.ns &&
         !(
           config.ignoredElements.length &&
           config.ignoredElements.some(function (ignore) {
             return isRegExp(ignore)
               ? ignore.test(vnode.tag)
               : ignore === vnode.tag
           })
         ) &&
         config.isUnknownElement(vnode.tag)
       )
     }
 
     var creatingElmInVPre = 0;
 
     function createElm (
       vnode,
       insertedVnodeQueue,
       parentElm,
       refElm,
       nested,
       ownerArray,
       index
     ) {
       if (isDef(vnode.elm) && isDef(ownerArray)) {
         // This vnode was used in a previous render!
         // now it's used as a new node, overwriting its elm would cause
         // potential patch errors down the road when it's used as an insertion
         // reference node. Instead, we clone the node on-demand before creating
         // associated DOM element for it.
         vnode = ownerArray[index] = cloneVNode(vnode);
       }
 
       vnode.isRootInsert = !nested; // for transition enter check
       if (createComponent(vnode, insertedVnodeQueue, parentElm, refElm)) {
         return
       }
 
       var data = vnode.data;
       var children = vnode.children;
       var tag = vnode.tag;
       if (isDef(tag)) {
         {
           if (data && data.pre) {
             creatingElmInVPre++;
           }
           if (isUnknownElement$$1(vnode, creatingElmInVPre)) {
             warn(
               'Unknown custom element: <' + tag + '> - did you ' +
               'register the component correctly? For recursive components, ' +
               'make sure to provide the "name" option.',
               vnode.context
             );
           }
         }
 
         vnode.elm = vnode.ns
           ? nodeOps.createElementNS(vnode.ns, tag)
           : nodeOps.createElement(tag, vnode);
         setScope(vnode);
 
         /* istanbul ignore if */
         {
           createChildren(vnode, children, insertedVnodeQueue);
           if (isDef(data)) {
             invokeCreateHooks(vnode, insertedVnodeQueue);
           }
           insert(parentElm, vnode.elm, refElm);
         }
 
         if (data && data.pre) {
           creatingElmInVPre--;
         }
       } else if (isTrue(vnode.isComment)) {
         vnode.elm = nodeOps.createComment(vnode.text);
         insert(parentElm, vnode.elm, refElm);
       } else {
         vnode.elm = nodeOps.createTextNode(vnode.text);
         insert(parentElm, vnode.elm, refElm);
       }
     }
 
     function createComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
       var i = vnode.data;
       if (isDef(i)) {
         var isReactivated = isDef(vnode.componentInstance) && i.keepAlive;
         if (isDef(i = i.hook) && isDef(i = i.init)) {
           i(vnode, false /* hydrating */);
         }
         // after calling the init hook, if the vnode is a child component
         // it should've created a child instance and mounted it. the child
         // component also has set the placeholder vnode's elm.
         // in that case we can just return the element and be done.
         if (isDef(vnode.componentInstance)) {
           initComponent(vnode, insertedVnodeQueue);
           insert(parentElm, vnode.elm, refElm);
           if (isTrue(isReactivated)) {
             reactivateComponent(vnode, insertedVnodeQueue, parentElm, refElm);
           }
           return true
         }
       }
     }
 
     function initComponent (vnode, insertedVnodeQueue) {
       if (isDef(vnode.data.pendingInsert)) {
         insertedVnodeQueue.push.apply(insertedVnodeQueue, vnode.data.pendingInsert);
         vnode.data.pendingInsert = null;
       }
       vnode.elm = vnode.componentInstance.$el;
       if (isPatchable(vnode)) {
         invokeCreateHooks(vnode, insertedVnodeQueue);
         setScope(vnode);
       } else {
         // empty component root.
         // skip all element-related modules except for ref (#3455)
         registerRef(vnode);
         // make sure to invoke the insert hook
         insertedVnodeQueue.push(vnode);
       }
     }
 
     function reactivateComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
       var i;
       // hack for #4339: a reactivated component with inner transition
       // does not trigger because the inner node's created hooks are not called
       // again. It's not ideal to involve module-specific logic in here but
       // there doesn't seem to be a better way to do it.
       var innerNode = vnode;
       while (innerNode.componentInstance) {
         innerNode = innerNode.componentInstance._vnode;
         if (isDef(i = innerNode.data) && isDef(i = i.transition)) {
           for (i = 0; i < cbs.activate.length; ++i) {
             cbs.activate[i](emptyNode, innerNode);
           }
           insertedVnodeQueue.push(innerNode);
           break
         }
       }
       // unlike a newly created component,
       // a reactivated keep-alive component doesn't insert itself
       insert(parentElm, vnode.elm, refElm);
     }
 
     function insert (parent, elm, ref$$1) {
       if (isDef(parent)) {
         if (isDef(ref$$1)) {
           if (nodeOps.parentNode(ref$$1) === parent) {
             nodeOps.insertBefore(parent, elm, ref$$1);
           }
         } else {
           nodeOps.appendChild(parent, elm);
         }
       }
     }
 
     function createChildren (vnode, children, insertedVnodeQueue) {
       if (Array.isArray(children)) {
         {
           checkDuplicateKeys(children);
         }
         for (var i = 0; i < children.length; ++i) {
           createElm(children[i], insertedVnodeQueue, vnode.elm, null, true, children, i);
         }
       } else if (isPrimitive(vnode.text)) {
         nodeOps.appendChild(vnode.elm, nodeOps.createTextNode(String(vnode.text)));
       }
     }
 
     function isPatchable (vnode) {
       while (vnode.componentInstance) {
         vnode = vnode.componentInstance._vnode;
       }
       return isDef(vnode.tag)
     }
 
     function invokeCreateHooks (vnode, insertedVnodeQueue) {
       for (var i$1 = 0; i$1 < cbs.create.length; ++i$1) {
         cbs.create[i$1](emptyNode, vnode);
       }
       i = vnode.data.hook; // Reuse variable
       if (isDef(i)) {
         if (isDef(i.create)) { i.create(emptyNode, vnode); }
         if (isDef(i.insert)) { insertedVnodeQueue.push(vnode); }
       }
     }
 
     // set scope id attribute for scoped CSS.
     // this is implemented as a special case to avoid the overhead
     // of going through the normal attribute patching process.
     function setScope (vnode) {
       var i;
       if (isDef(i = vnode.fnScopeId)) {
         nodeOps.setStyleScope(vnode.elm, i);
       } else {
         var ancestor = vnode;
         while (ancestor) {
           if (isDef(i = ancestor.context) && isDef(i = i.$options._scopeId)) {
             nodeOps.setStyleScope(vnode.elm, i);
           }
           ancestor = ancestor.parent;
         }
       }
       // for slot content they should also get the scopeId from the host instance.
       if (isDef(i = activeInstance) &&
         i !== vnode.context &&
         i !== vnode.fnContext &&
         isDef(i = i.$options._scopeId)
       ) {
         nodeOps.setStyleScope(vnode.elm, i);
       }
     }
 
     function addVnodes (parentElm, refElm, vnodes, startIdx, endIdx, insertedVnodeQueue) {
       for (; startIdx <= endIdx; ++startIdx) {
         createElm(vnodes[startIdx], insertedVnodeQueue, parentElm, refElm, false, vnodes, startIdx);
       }
     }
 
     function invokeDestroyHook (vnode) {
       var i, j;
       var data = vnode.data;
       if (isDef(data)) {
         if (isDef(i = data.hook) && isDef(i = i.destroy)) { i(vnode); }
         for (i = 0; i < cbs.destroy.length; ++i) { cbs.destroy[i](vnode); }
       }
       if (isDef(i = vnode.children)) {
         for (j = 0; j < vnode.children.length; ++j) {
           invokeDestroyHook(vnode.children[j]);
         }
       }
     }
 
     function removeVnodes (vnodes, startIdx, endIdx) {
       for (; startIdx <= endIdx; ++startIdx) {
         var ch = vnodes[startIdx];
         if (isDef(ch)) {
           if (isDef(ch.tag)) {
             removeAndInvokeRemoveHook(ch);
             invokeDestroyHook(ch);
           } else { // Text node
             removeNode(ch.elm);
           }
         }
       }
     }
 
     function removeAndInvokeRemoveHook (vnode, rm) {
       if (isDef(rm) || isDef(vnode.data)) {
         var i;
         var listeners = cbs.remove.length + 1;
         if (isDef(rm)) {
           // we have a recursively passed down rm callback
           // increase the listeners count
           rm.listeners += listeners;
         } else {
           // directly removing
           rm = createRmCb(vnode.elm, listeners);
         }
         // recursively invoke hooks on child component root node
         if (isDef(i = vnode.componentInstance) && isDef(i = i._vnode) && isDef(i.data)) {
           removeAndInvokeRemoveHook(i, rm);
         }
         for (i = 0; i < cbs.remove.length; ++i) {
           cbs.remove[i](vnode, rm);
         }
         if (isDef(i = vnode.data.hook) && isDef(i = i.remove)) {
           i(vnode, rm);
         } else {
           rm();
         }
       } else {
         removeNode(vnode.elm);
       }
     }
 
     function updateChildren (parentElm, oldCh, newCh, insertedVnodeQueue, removeOnly) {
       var oldStartIdx = 0;
       var newStartIdx = 0;
       var oldEndIdx = oldCh.length - 1;
       var oldStartVnode = oldCh[0];
       var oldEndVnode = oldCh[oldEndIdx];
       var newEndIdx = newCh.length - 1;
       var newStartVnode = newCh[0];
       var newEndVnode = newCh[newEndIdx];
       var oldKeyToIdx, idxInOld, vnodeToMove, refElm;
 
       // removeOnly is a special flag used only by <transition-group>
       // to ensure removed elements stay in correct relative positions
       // during leaving transitions
       var canMove = !removeOnly;
 
       {
         checkDuplicateKeys(newCh);
       }
 
       while (oldStartIdx <= oldEndIdx && newStartIdx <= newEndIdx) {
         if (isUndef(oldStartVnode)) {
           oldStartVnode = oldCh[++oldStartIdx]; // Vnode has been moved left
         } else if (isUndef(oldEndVnode)) {
           oldEndVnode = oldCh[--oldEndIdx];
         } else if (sameVnode(oldStartVnode, newStartVnode)) {
           patchVnode(oldStartVnode, newStartVnode, insertedVnodeQueue, newCh, newStartIdx);
           oldStartVnode = oldCh[++oldStartIdx];
           newStartVnode = newCh[++newStartIdx];
         } else if (sameVnode(oldEndVnode, newEndVnode)) {
           patchVnode(oldEndVnode, newEndVnode, insertedVnodeQueue, newCh, newEndIdx);
           oldEndVnode = oldCh[--oldEndIdx];
           newEndVnode = newCh[--newEndIdx];
         } else if (sameVnode(oldStartVnode, newEndVnode)) { // Vnode moved right
           patchVnode(oldStartVnode, newEndVnode, insertedVnodeQueue, newCh, newEndIdx);
           canMove && nodeOps.insertBefore(parentElm, oldStartVnode.elm, nodeOps.nextSibling(oldEndVnode.elm));
           oldStartVnode = oldCh[++oldStartIdx];
           newEndVnode = newCh[--newEndIdx];
         } else if (sameVnode(oldEndVnode, newStartVnode)) { // Vnode moved left
           patchVnode(oldEndVnode, newStartVnode, insertedVnodeQueue, newCh, newStartIdx);
           canMove && nodeOps.insertBefore(parentElm, oldEndVnode.elm, oldStartVnode.elm);
           oldEndVnode = oldCh[--oldEndIdx];
           newStartVnode = newCh[++newStartIdx];
         } else {
           if (isUndef(oldKeyToIdx)) { oldKeyToIdx = createKeyToOldIdx(oldCh, oldStartIdx, oldEndIdx); }
           idxInOld = isDef(newStartVnode.key)
             ? oldKeyToIdx[newStartVnode.key]
             : findIdxInOld(newStartVnode, oldCh, oldStartIdx, oldEndIdx);
           if (isUndef(idxInOld)) { // New element
             createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm, false, newCh, newStartIdx);
           } else {
             vnodeToMove = oldCh[idxInOld];
             if (sameVnode(vnodeToMove, newStartVnode)) {
               patchVnode(vnodeToMove, newStartVnode, insertedVnodeQueue, newCh, newStartIdx);
               oldCh[idxInOld] = undefined;
               canMove && nodeOps.insertBefore(parentElm, vnodeToMove.elm, oldStartVnode.elm);
             } else {
               // same key but different element. treat as new element
               createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm, false, newCh, newStartIdx);
             }
           }
           newStartVnode = newCh[++newStartIdx];
         }
       }
       if (oldStartIdx > oldEndIdx) {
         refElm = isUndef(newCh[newEndIdx + 1]) ? null : newCh[newEndIdx + 1].elm;
         addVnodes(parentElm, refElm, newCh, newStartIdx, newEndIdx, insertedVnodeQueue);
       } else if (newStartIdx > newEndIdx) {
         removeVnodes(oldCh, oldStartIdx, oldEndIdx);
       }
     }
 
     function checkDuplicateKeys (children) {
       var seenKeys = {};
       for (var i = 0; i < children.length; i++) {
         var vnode = children[i];
         var key = vnode.key;
         if (isDef(key)) {
           if (seenKeys[key]) {
             warn(
               ("Duplicate keys detected: '" + key + "'. This may cause an update error."),
               vnode.context
             );
           } else {
             seenKeys[key] = true;
           }
         }
       }
     }
 
     function findIdxInOld (node, oldCh, start, end) {
       for (var i = start; i < end; i++) {
         var c = oldCh[i];
         if (isDef(c) && sameVnode(node, c)) { return i }
       }
     }
 
     function patchVnode (
       oldVnode,
       vnode,
       insertedVnodeQueue,
       ownerArray,
       index,
       removeOnly
     ) {
       if (oldVnode === vnode) {
         return
       }
 
       if (isDef(vnode.elm) && isDef(ownerArray)) {
         // clone reused vnode
         vnode = ownerArray[index] = cloneVNode(vnode);
       }
 
       var elm = vnode.elm = oldVnode.elm;
 
       if (isTrue(oldVnode.isAsyncPlaceholder)) {
         if (isDef(vnode.asyncFactory.resolved)) {
           hydrate(oldVnode.elm, vnode, insertedVnodeQueue);
         } else {
           vnode.isAsyncPlaceholder = true;
         }
         return
       }
 
       // reuse element for static trees.
       // note we only do this if the vnode is cloned -
       // if the new node is not cloned it means the render functions have been
       // reset by the hot-reload-api and we need to do a proper re-render.
       if (isTrue(vnode.isStatic) &&
         isTrue(oldVnode.isStatic) &&
         vnode.key === oldVnode.key &&
         (isTrue(vnode.isCloned) || isTrue(vnode.isOnce))
       ) {
         vnode.componentInstance = oldVnode.componentInstance;
         return
       }
 
       var i;
       var data = vnode.data;
       if (isDef(data) && isDef(i = data.hook) && isDef(i = i.prepatch)) {
         i(oldVnode, vnode);
       }
 
       var oldCh = oldVnode.children;
       var ch = vnode.children;
       if (isDef(data) && isPatchable(vnode)) {
         for (i = 0; i < cbs.update.length; ++i) { cbs.update[i](oldVnode, vnode); }
         if (isDef(i = data.hook) && isDef(i = i.update)) { i(oldVnode, vnode); }
       }
       if (isUndef(vnode.text)) {
         if (isDef(oldCh) && isDef(ch)) {
           if (oldCh !== ch) { updateChildren(elm, oldCh, ch, insertedVnodeQueue, removeOnly); }
         } else if (isDef(ch)) {
           {
             checkDuplicateKeys(ch);
           }
           if (isDef(oldVnode.text)) { nodeOps.setTextContent(elm, ''); }
           addVnodes(elm, null, ch, 0, ch.length - 1, insertedVnodeQueue);
         } else if (isDef(oldCh)) {
           removeVnodes(oldCh, 0, oldCh.length - 1);
         } else if (isDef(oldVnode.text)) {
           nodeOps.setTextContent(elm, '');
         }
       } else if (oldVnode.text !== vnode.text) {
         nodeOps.setTextContent(elm, vnode.text);
       }
       if (isDef(data)) {
         if (isDef(i = data.hook) && isDef(i = i.postpatch)) { i(oldVnode, vnode); }
       }
     }
 
     function invokeInsertHook (vnode, queue, initial) {
       // delay insert hooks for component root nodes, invoke them after the
       // element is really inserted
       if (isTrue(initial) && isDef(vnode.parent)) {
         vnode.parent.data.pendingInsert = queue;
       } else {
         for (var i = 0; i < queue.length; ++i) {
           queue[i].data.hook.insert(queue[i]);
         }
       }
     }
 
     var hydrationBailed = false;
     // list of modules that can skip create hook during hydration because they
     // are already rendered on the client or has no need for initialization
     // Note: style is excluded because it relies on initial clone for future
     // deep updates (#7063).
     var isRenderedModule = makeMap('attrs,class,staticClass,staticStyle,key');
 
     // Note: this is a browser-only function so we can assume elms are DOM nodes.
     function hydrate (elm, vnode, insertedVnodeQueue, inVPre) {
       var i;
       var tag = vnode.tag;
       var data = vnode.data;
       var children = vnode.children;
       inVPre = inVPre || (data && data.pre);
       vnode.elm = elm;
 
       if (isTrue(vnode.isComment) && isDef(vnode.asyncFactory)) {
         vnode.isAsyncPlaceholder = true;
         return true
       }
       // assert node match
       {
         if (!assertNodeMatch(elm, vnode, inVPre)) {
           return false
         }
       }
       if (isDef(data)) {
         if (isDef(i = data.hook) && isDef(i = i.init)) { i(vnode, true /* hydrating */); }
         if (isDef(i = vnode.componentInstance)) {
           // child component. it should have hydrated its own tree.
           initComponent(vnode, insertedVnodeQueue);
           return true
         }
       }
       if (isDef(tag)) {
         if (isDef(children)) {
           // empty element, allow client to pick up and populate children
           if (!elm.hasChildNodes()) {
             createChildren(vnode, children, insertedVnodeQueue);
           } else {
             // v-html and domProps: innerHTML
             if (isDef(i = data) && isDef(i = i.domProps) && isDef(i = i.innerHTML)) {
               if (i !== elm.innerHTML) {
                 /* istanbul ignore if */
                 if (typeof console !== 'undefined' &&
                   !hydrationBailed
                 ) {
                   hydrationBailed = true;
                   console.warn('Parent: ', elm);
                   console.warn('server innerHTML: ', i);
                   console.warn('client innerHTML: ', elm.innerHTML);
                 }
                 return false
               }
             } else {
               // iterate and compare children lists
               var childrenMatch = true;
               var childNode = elm.firstChild;
               for (var i$1 = 0; i$1 < children.length; i$1++) {
                 if (!childNode || !hydrate(childNode, children[i$1], insertedVnodeQueue, inVPre)) {
                   childrenMatch = false;
                   break
                 }
                 childNode = childNode.nextSibling;
               }
               // if childNode is not null, it means the actual childNodes list is
               // longer than the virtual children list.
               if (!childrenMatch || childNode) {
                 /* istanbul ignore if */
                 if (typeof console !== 'undefined' &&
                   !hydrationBailed
                 ) {
                   hydrationBailed = true;
                   console.warn('Parent: ', elm);
                   console.warn('Mismatching childNodes vs. VNodes: ', elm.childNodes, children);
                 }
                 return false
               }
             }
           }
         }
         if (isDef(data)) {
           var fullInvoke = false;
           for (var key in data) {
             if (!isRenderedModule(key)) {
               fullInvoke = true;
               invokeCreateHooks(vnode, insertedVnodeQueue);
               break
             }
           }
           if (!fullInvoke && data['class']) {
             // ensure collecting deps for deep class bindings for future updates
             traverse(data['class']);
           }
         }
       } else if (elm.data !== vnode.text) {
         elm.data = vnode.text;
       }
       return true
     }
 
     function assertNodeMatch (node, vnode, inVPre) {
       if (isDef(vnode.tag)) {
         return vnode.tag.indexOf('vue-component') === 0 || (
           !isUnknownElement$$1(vnode, inVPre) &&
           vnode.tag.toLowerCase() === (node.tagName && node.tagName.toLowerCase())
         )
       } else {
         return node.nodeType === (vnode.isComment ? 8 : 3)
       }
     }
 
     return function patch (oldVnode, vnode, hydrating, removeOnly) {
       if (isUndef(vnode)) {
         if (isDef(oldVnode)) { invokeDestroyHook(oldVnode); }
         return
       }
 
       var isInitialPatch = false;
       var insertedVnodeQueue = [];
 
       if (isUndef(oldVnode)) {
         // empty mount (likely as component), create new root element
         isInitialPatch = true;
         createElm(vnode, insertedVnodeQueue);
       } else {
         var isRealElement = isDef(oldVnode.nodeType);
         if (!isRealElement && sameVnode(oldVnode, vnode)) {
           // patch existing root node
           patchVnode(oldVnode, vnode, insertedVnodeQueue, null, null, removeOnly);
         } else {
           if (isRealElement) {
             // mounting to a real element
             // check if this is server-rendered content and if we can perform
             // a successful hydration.
             if (oldVnode.nodeType === 1 && oldVnode.hasAttribute(SSR_ATTR)) {
               oldVnode.removeAttribute(SSR_ATTR);
               hydrating = true;
             }
             if (isTrue(hydrating)) {
               if (hydrate(oldVnode, vnode, insertedVnodeQueue)) {
                 invokeInsertHook(vnode, insertedVnodeQueue, true);
                 return oldVnode
               } else {
                 warn(
                   'The client-side rendered virtual DOM tree is not matching ' +
                   'server-rendered content. This is likely caused by incorrect ' +
                   'HTML markup, for example nesting block-level elements inside ' +
                   '<p>, or missing <tbody>. Bailing hydration and performing ' +
                   'full client-side render.'
                 );
               }
             }
             // either not server-rendered, or hydration failed.
             // create an empty node and replace it
             oldVnode = emptyNodeAt(oldVnode);
           }
 
           // replacing existing element
           var oldElm = oldVnode.elm;
           var parentElm = nodeOps.parentNode(oldElm);
 
           // create new node
           createElm(
             vnode,
             insertedVnodeQueue,
             // extremely rare edge case: do not insert if old element is in a
             // leaving transition. Only happens when combining transition +
             // keep-alive + HOCs. (#4590)
             oldElm._leaveCb ? null : parentElm,
             nodeOps.nextSibling(oldElm)
           );
 
           // update parent placeholder node element, recursively
           if (isDef(vnode.parent)) {
             var ancestor = vnode.parent;
             var patchable = isPatchable(vnode);
             while (ancestor) {
               for (var i = 0; i < cbs.destroy.length; ++i) {
                 cbs.destroy[i](ancestor);
               }
               ancestor.elm = vnode.elm;
               if (patchable) {
                 for (var i$1 = 0; i$1 < cbs.create.length; ++i$1) {
                   cbs.create[i$1](emptyNode, ancestor);
                 }
                 // #6513
                 // invoke insert hooks that may have been merged by create hooks.
                 // e.g. for directives that uses the "inserted" hook.
                 var insert = ancestor.data.hook.insert;
                 if (insert.merged) {
                   // start at index 1 to avoid re-invoking component mounted hook
                   for (var i$2 = 1; i$2 < insert.fns.length; i$2++) {
                     insert.fns[i$2]();
                   }
                 }
               } else {
                 registerRef(ancestor);
               }
               ancestor = ancestor.parent;
             }
           }
 
           // destroy old node
           if (isDef(parentElm)) {
             removeVnodes([oldVnode], 0, 0);
           } else if (isDef(oldVnode.tag)) {
             invokeDestroyHook(oldVnode);
           }
         }
       }
 
       invokeInsertHook(vnode, insertedVnodeQueue, isInitialPatch);
       return vnode.elm
     }
   }
 
   /*  */
 
   var directives = {
     create: updateDirectives,
     update: updateDirectives,
     destroy: function unbindDirectives (vnode) {
       updateDirectives(vnode, emptyNode);
     }
   };
 
   function updateDirectives (oldVnode, vnode) {
     if (oldVnode.data.directives || vnode.data.directives) {
       _update(oldVnode, vnode);
     }
   }
 
   function _update (oldVnode, vnode) {
     var isCreate = oldVnode === emptyNode;
     var isDestroy = vnode === emptyNode;
     var oldDirs = normalizeDirectives$1(oldVnode.data.directives, oldVnode.context);
     var newDirs = normalizeDirectives$1(vnode.data.directives, vnode.context);
 
     var dirsWithInsert = [];
     var dirsWithPostpatch = [];
 
     var key, oldDir, dir;
     for (key in newDirs) {
       oldDir = oldDirs[key];
       dir = newDirs[key];
       if (!oldDir) {
         // new directive, bind
         callHook$1(dir, 'bind', vnode, oldVnode);
         if (dir.def && dir.def.inserted) {
           dirsWithInsert.push(dir);
         }
       } else {
         // existing directive, update
         dir.oldValue = oldDir.value;
         dir.oldArg = oldDir.arg;
         callHook$1(dir, 'update', vnode, oldVnode);
         if (dir.def && dir.def.componentUpdated) {
           dirsWithPostpatch.push(dir);
         }
       }
     }
 
     if (dirsWithInsert.length) {
       var callInsert = function () {
         for (var i = 0; i < dirsWithInsert.length; i++) {
           callHook$1(dirsWithInsert[i], 'inserted', vnode, oldVnode);
         }
       };
       if (isCreate) {
         mergeVNodeHook(vnode, 'insert', callInsert);
       } else {
         callInsert();
       }
     }
 
     if (dirsWithPostpatch.length) {
       mergeVNodeHook(vnode, 'postpatch', function () {
         for (var i = 0; i < dirsWithPostpatch.length; i++) {
           callHook$1(dirsWithPostpatch[i], 'componentUpdated', vnode, oldVnode);
         }
       });
     }
 
     if (!isCreate) {
       for (key in oldDirs) {
         if (!newDirs[key]) {
           // no longer present, unbind
           callHook$1(oldDirs[key], 'unbind', oldVnode, oldVnode, isDestroy);
         }
       }
     }
   }
 
   var emptyModifiers = Object.create(null);
 
   function normalizeDirectives$1 (
     dirs,
     vm
   ) {
     var res = Object.create(null);
     if (!dirs) {
       // $flow-disable-line
       return res
     }
     var i, dir;
     for (i = 0; i < dirs.length; i++) {
       dir = dirs[i];
       if (!dir.modifiers) {
         // $flow-disable-line
         dir.modifiers = emptyModifiers;
       }
       res[getRawDirName(dir)] = dir;
       dir.def = resolveAsset(vm.$options, 'directives', dir.name, true);
     }
     // $flow-disable-line
     return res
   }
 
   function getRawDirName (dir) {
     return dir.rawName || ((dir.name) + "." + (Object.keys(dir.modifiers || {}).join('.')))
   }
 
   function callHook$1 (dir, hook, vnode, oldVnode, isDestroy) {
     var fn = dir.def && dir.def[hook];
     if (fn) {
       try {
         fn(vnode.elm, dir, vnode, oldVnode, isDestroy);
       } catch (e) {
         handleError(e, vnode.context, ("directive " + (dir.name) + " " + hook + " hook"));
       }
     }
   }
 
   var baseModules = [
     ref,
     directives
   ];
 
   /*  */
 
   function updateAttrs (oldVnode, vnode) {
     var opts = vnode.componentOptions;
     if (isDef(opts) && opts.Ctor.options.inheritAttrs === false) {
       return
     }
     if (isUndef(oldVnode.data.attrs) && isUndef(vnode.data.attrs)) {
       return
     }
     var key, cur, old;
     var elm = vnode.elm;
     var oldAttrs = oldVnode.data.attrs || {};
     var attrs = vnode.data.attrs || {};
     // clone observed objects, as the user probably wants to mutate it
     if (isDef(attrs.__ob__)) {
       attrs = vnode.data.attrs = extend({}, attrs);
     }
 
     for (key in attrs) {
       cur = attrs[key];
       old = oldAttrs[key];
       if (old !== cur) {
         setAttr(elm, key, cur);
       }
     }
     // #4391: in IE9, setting type can reset value for input[type=radio]
     // #6666: IE/Edge forces progress value down to 1 before setting a max
     /* istanbul ignore if */
     if ((isIE || isEdge) && attrs.value !== oldAttrs.value) {
       setAttr(elm, 'value', attrs.value);
     }
     for (key in oldAttrs) {
       if (isUndef(attrs[key])) {
         if (isXlink(key)) {
           elm.removeAttributeNS(xlinkNS, getXlinkProp(key));
         } else if (!isEnumeratedAttr(key)) {
           elm.removeAttribute(key);
         }
       }
     }
   }
 
   function setAttr (el, key, value) {
     if (el.tagName.indexOf('-') > -1) {
       baseSetAttr(el, key, value);
     } else if (isBooleanAttr(key)) {
       // set attribute for blank value
       // e.g. <option disabled>Select one</option>
       if (isFalsyAttrValue(value)) {
         el.removeAttribute(key);
       } else {
         // technically allowfullscreen is a boolean attribute for <iframe>,
         // but Flash expects a value of "true" when used on <embed> tag
         value = key === 'allowfullscreen' && el.tagName === 'EMBED'
           ? 'true'
           : key;
         el.setAttribute(key, value);
       }
     } else if (isEnumeratedAttr(key)) {
       el.setAttribute(key, convertEnumeratedValue(key, value));
     } else if (isXlink(key)) {
       if (isFalsyAttrValue(value)) {
         el.removeAttributeNS(xlinkNS, getXlinkProp(key));
       } else {
         el.setAttributeNS(xlinkNS, key, value);
       }
     } else {
       baseSetAttr(el, key, value);
     }
   }
 
   function baseSetAttr (el, key, value) {
     if (isFalsyAttrValue(value)) {
       el.removeAttribute(key);
     } else {
       // #7138: IE10 & 11 fires input event when setting placeholder on
       // <textarea>... block the first input event and remove the blocker
       // immediately.
       /* istanbul ignore if */
       if (
         isIE && !isIE9 &&
         el.tagName === 'TEXTAREA' &&
         key === 'placeholder' && value !== '' && !el.__ieph
       ) {
         var blocker = function (e) {
           e.stopImmediatePropagation();
           el.removeEventListener('input', blocker);
         };
         el.addEventListener('input', blocker);
         // $flow-disable-line
         el.__ieph = true; /* IE placeholder patched */
       }
       el.setAttribute(key, value);
     }
   }
 
   var attrs = {
     create: updateAttrs,
     update: updateAttrs
   };
 
   /*  */
 
   function updateClass (oldVnode, vnode) {
     var el = vnode.elm;
     var data = vnode.data;
     var oldData = oldVnode.data;
     if (
       isUndef(data.staticClass) &&
       isUndef(data.class) && (
         isUndef(oldData) || (
           isUndef(oldData.staticClass) &&
           isUndef(oldData.class)
         )
       )
     ) {
       return
     }
 
     var cls = genClassForVnode(vnode);
 
     // handle transition classes
     var transitionClass = el._transitionClasses;
     if (isDef(transitionClass)) {
       cls = concat(cls, stringifyClass(transitionClass));
     }
 
     // set the class
     if (cls !== el._prevClass) {
       el.setAttribute('class', cls);
       el._prevClass = cls;
     }
   }
 
   var klass = {
     create: updateClass,
     update: updateClass
   };
 
   /*  */
 
   var validDivisionCharRE = /[\w).+\-_$\]]/;
 
   function parseFilters (exp) {
     var inSingle = false;
     var inDouble = false;
     var inTemplateString = false;
     var inRegex = false;
     var curly = 0;
     var square = 0;
     var paren = 0;
     var lastFilterIndex = 0;
     var c, prev, i, expression, filters;
 
     for (i = 0; i < exp.length; i++) {
       prev = c;
       c = exp.charCodeAt(i);
       if (inSingle) {
         if (c === 0x27 && prev !== 0x5C) { inSingle = false; }
       } else if (inDouble) {
         if (c === 0x22 && prev !== 0x5C) { inDouble = false; }
       } else if (inTemplateString) {
         if (c === 0x60 && prev !== 0x5C) { inTemplateString = false; }
       } else if (inRegex) {
         if (c === 0x2f && prev !== 0x5C) { inRegex = false; }
       } else if (
         c === 0x7C && // pipe
         exp.charCodeAt(i + 1) !== 0x7C &&
         exp.charCodeAt(i - 1) !== 0x7C &&
         !curly && !square && !paren
       ) {
         if (expression === undefined) {
           // first filter, end of expression
           lastFilterIndex = i + 1;
           expression = exp.slice(0, i).trim();
         } else {
           pushFilter();
         }
       } else {
         switch (c) {
           case 0x22: inDouble = true; break         // "
           case 0x27: inSingle = true; break         // '
           case 0x60: inTemplateString = true; break // `
           case 0x28: paren++; break                 // (
           case 0x29: paren--; break                 // )
           case 0x5B: square++; break                // [
           case 0x5D: square--; break                // ]
           case 0x7B: curly++; break                 // {
           case 0x7D: curly--; break                 // }
         }
         if (c === 0x2f) { // /
           var j = i - 1;
           var p = (void 0);
           // find first non-whitespace prev char
           for (; j >= 0; j--) {
             p = exp.charAt(j);
             if (p !== ' ') { break }
           }
           if (!p || !validDivisionCharRE.test(p)) {
             inRegex = true;
           }
         }
       }
     }
 
     if (expression === undefined) {
       expression = exp.slice(0, i).trim();
     } else if (lastFilterIndex !== 0) {
       pushFilter();
     }
 
     function pushFilter () {
       (filters || (filters = [])).push(exp.slice(lastFilterIndex, i).trim());
       lastFilterIndex = i + 1;
     }
 
     if (filters) {
       for (i = 0; i < filters.length; i++) {
         expression = wrapFilter(expression, filters[i]);
       }
     }
 
     return expression
   }
 
   function wrapFilter (exp, filter) {
     var i = filter.indexOf('(');
     if (i < 0) {
       // _f: resolveFilter
       return ("_f(\"" + filter + "\")(" + exp + ")")
     } else {
       var name = filter.slice(0, i);
       var args = filter.slice(i + 1);
       return ("_f(\"" + name + "\")(" + exp + (args !== ')' ? ',' + args : args))
     }
   }
 
   /*  */
 
 
 
   /* eslint-disable no-unused-vars */
   function baseWarn (msg, range) {
     console.error(("[Vue compiler]: " + msg));
   }
   /* eslint-enable no-unused-vars */
 
   function pluckModuleFunction (
     modules,
     key
   ) {
     return modules
       ? modules.map(function (m) { return m[key]; }).filter(function (_) { return _; })
       : []
   }
 
   function addProp (el, name, value, range, dynamic) {
     (el.props || (el.props = [])).push(rangeSetItem({ name: name, value: value, dynamic: dynamic }, range));
     el.plain = false;
   }
 
   function addAttr (el, name, value, range, dynamic) {
     var attrs = dynamic
       ? (el.dynamicAttrs || (el.dynamicAttrs = []))
       : (el.attrs || (el.attrs = []));
     attrs.push(rangeSetItem({ name: name, value: value, dynamic: dynamic }, range));
     el.plain = false;
   }
 
   // add a raw attr (use this in preTransforms)
   function addRawAttr (el, name, value, range) {
     el.attrsMap[name] = value;
     el.attrsList.push(rangeSetItem({ name: name, value: value }, range));
   }
 
   function addDirective (
     el,
     name,
     rawName,
     value,
     arg,
     isDynamicArg,
     modifiers,
     range
   ) {
     (el.directives || (el.directives = [])).push(rangeSetItem({
       name: name,
       rawName: rawName,
       value: value,
       arg: arg,
       isDynamicArg: isDynamicArg,
       modifiers: modifiers
     }, range));
     el.plain = false;
   }
 
   function prependModifierMarker (symbol, name, dynamic) {
     return dynamic
       ? ("_p(" + name + ",\"" + symbol + "\")")
       : symbol + name // mark the event as captured
   }
 
   function addHandler (
     el,
     name,
     value,
     modifiers,
     important,
     warn,
     range,
     dynamic
   ) {
     modifiers = modifiers || emptyObject;
     // warn prevent and passive modifier
     /* istanbul ignore if */
     if (
       warn &&
       modifiers.prevent && modifiers.passive
     ) {
       warn(
         'passive and prevent can\'t be used together. ' +
         'Passive handler can\'t prevent default event.',
         range
       );
     }
 
     // normalize click.right and click.middle since they don't actually fire
     // this is technically browser-specific, but at least for now browsers are
     // the only target envs that have right/middle clicks.
     if (modifiers.right) {
       if (dynamic) {
         name = "(" + name + ")==='click'?'contextmenu':(" + name + ")";
       } else if (name === 'click') {
         name = 'contextmenu';
         delete modifiers.right;
       }
     } else if (modifiers.middle) {
       if (dynamic) {
         name = "(" + name + ")==='click'?'mouseup':(" + name + ")";
       } else if (name === 'click') {
         name = 'mouseup';
       }
     }
 
     // check capture modifier
     if (modifiers.capture) {
       delete modifiers.capture;
       name = prependModifierMarker('!', name, dynamic);
     }
     if (modifiers.once) {
       delete modifiers.once;
       name = prependModifierMarker('~', name, dynamic);
     }
     /* istanbul ignore if */
     if (modifiers.passive) {
       delete modifiers.passive;
       name = prependModifierMarker('&', name, dynamic);
     }
 
     var events;
     if (modifiers.native) {
       delete modifiers.native;
       events = el.nativeEvents || (el.nativeEvents = {});
     } else {
       events = el.events || (el.events = {});
     }
 
     var newHandler = rangeSetItem({ value: value.trim(), dynamic: dynamic }, range);
     if (modifiers !== emptyObject) {
       newHandler.modifiers = modifiers;
     }
 
     var handlers = events[name];
     /* istanbul ignore if */
     if (Array.isArray(handlers)) {
       important ? handlers.unshift(newHandler) : handlers.push(newHandler);
     } else if (handlers) {
       events[name] = important ? [newHandler, handlers] : [handlers, newHandler];
     } else {
       events[name] = newHandler;
     }
 
     el.plain = false;
   }
 
   function getRawBindingAttr (
     el,
     name
   ) {
     return el.rawAttrsMap[':' + name] ||
       el.rawAttrsMap['v-bind:' + name] ||
       el.rawAttrsMap[name]
   }
 
   function getBindingAttr (
     el,
     name,
     getStatic
   ) {
     var dynamicValue =
       getAndRemoveAttr(el, ':' + name) ||
       getAndRemoveAttr(el, 'v-bind:' + name);
     if (dynamicValue != null) {
       return parseFilters(dynamicValue)
     } else if (getStatic !== false) {
       var staticValue = getAndRemoveAttr(el, name);
       if (staticValue != null) {
         return JSON.stringify(staticValue)
       }
     }
   }
 
   // note: this only removes the attr from the Array (attrsList) so that it
   // doesn't get processed by processAttrs.
   // By default it does NOT remove it from the map (attrsMap) because the map is
   // needed during codegen.
   function getAndRemoveAttr (
     el,
     name,
     removeFromMap
   ) {
     var val;
     if ((val = el.attrsMap[name]) != null) {
       var list = el.attrsList;
       for (var i = 0, l = list.length; i < l; i++) {
         if (list[i].name === name) {
           list.splice(i, 1);
           break
         }
       }
     }
     if (removeFromMap) {
       delete el.attrsMap[name];
     }
     return val
   }
 
   function getAndRemoveAttrByRegex (
     el,
     name
   ) {
     var list = el.attrsList;
     for (var i = 0, l = list.length; i < l; i++) {
       var attr = list[i];
       if (name.test(attr.name)) {
         list.splice(i, 1);
         return attr
       }
     }
   }
 
   function rangeSetItem (
     item,
     range
   ) {
     if (range) {
       if (range.start != null) {
         item.start = range.start;
       }
       if (range.end != null) {
         item.end = range.end;
       }
     }
     return item
   }
 
   /*  */
 
   /**
    * Cross-platform code generation for component v-model
    */
   function genComponentModel (
     el,
     value,
     modifiers
   ) {
     var ref = modifiers || {};
     var number = ref.number;
     var trim = ref.trim;
 
     var baseValueExpression = '$$v';
     var valueExpression = baseValueExpression;
     if (trim) {
       valueExpression =
         "(typeof " + baseValueExpression + " === 'string'" +
         "? " + baseValueExpression + ".trim()" +
         ": " + baseValueExpression + ")";
     }
     if (number) {
       valueExpression = "_n(" + valueExpression + ")";
     }
     var assignment = genAssignmentCode(value, valueExpression);
 
     el.model = {
       value: ("(" + value + ")"),
       expression: JSON.stringify(value),
       callback: ("function (" + baseValueExpression + ") {" + assignment + "}")
     };
   }
 
   /**
    * Cross-platform codegen helper for generating v-model value assignment code.
    */
   function genAssignmentCode (
     value,
     assignment
   ) {
     var res = parseModel(value);
     if (res.key === null) {
       return (value + "=" + assignment)
     } else {
       return ("$set(" + (res.exp) + ", " + (res.key) + ", " + assignment + ")")
     }
   }
 
   /**
    * Parse a v-model expression into a base path and a final key segment.
    * Handles both dot-path and possible square brackets.
    *
    * Possible cases:
    *
    * - test
    * - test[key]
    * - test[test1[key]]
    * - test["a"][key]
    * - xxx.test[a[a].test1[key]]
    * - test.xxx.a["asa"][test1[key]]
    *
    */
 
   var len, str, chr, index$1, expressionPos, expressionEndPos;
 
 
 
   function parseModel (val) {
     // Fix https://github.com/vuejs/vue/pull/7730
     // allow v-model="obj.val " (trailing whitespace)
     val = val.trim();
     len = val.length;
 
     if (val.indexOf('[') < 0 || val.lastIndexOf(']') < len - 1) {
       index$1 = val.lastIndexOf('.');
       if (index$1 > -1) {
         return {
           exp: val.slice(0, index$1),
           key: '"' + val.slice(index$1 + 1) + '"'
         }
       } else {
         return {
           exp: val,
           key: null
         }
       }
     }
 
     str = val;
     index$1 = expressionPos = expressionEndPos = 0;
 
     while (!eof()) {
       chr = next();
       /* istanbul ignore if */
       if (isStringStart(chr)) {
         parseString(chr);
       } else if (chr === 0x5B) {
         parseBracket(chr);
       }
     }
 
     return {
       exp: val.slice(0, expressionPos),
       key: val.slice(expressionPos + 1, expressionEndPos)
     }
   }
 
   function next () {
     return str.charCodeAt(++index$1)
   }
 
   function eof () {
     return index$1 >= len
   }
 
   function isStringStart (chr) {
     return chr === 0x22 || chr === 0x27
   }
 
   function parseBracket (chr) {
     var inBracket = 1;
     expressionPos = index$1;
     while (!eof()) {
       chr = next();
       if (isStringStart(chr)) {
         parseString(chr);
         continue
       }
       if (chr === 0x5B) { inBracket++; }
       if (chr === 0x5D) { inBracket--; }
       if (inBracket === 0) {
         expressionEndPos = index$1;
         break
       }
     }
   }
 
   function parseString (chr) {
     var stringQuote = chr;
     while (!eof()) {
       chr = next();
       if (chr === stringQuote) {
         break
       }
     }
   }
 
   /*  */
 
   var warn$1;
 
   // in some cases, the event used has to be determined at runtime
   // so we used some reserved tokens during compile.
   var RANGE_TOKEN = '__r';
   var CHECKBOX_RADIO_TOKEN = '__c';
 
   function model (
     el,
     dir,
     _warn
   ) {
     warn$1 = _warn;
     var value = dir.value;
     var modifiers = dir.modifiers;
     var tag = el.tag;
     var type = el.attrsMap.type;
 
     {
       // inputs with type="file" are read only and setting the input's
       // value will throw an error.
       if (tag === 'input' && type === 'file') {
         warn$1(
           "<" + (el.tag) + " v-model=\"" + value + "\" type=\"file\">:\n" +
           "File inputs are read only. Use a v-on:change listener instead.",
           el.rawAttrsMap['v-model']
         );
       }
     }
 
     if (el.component) {
       genComponentModel(el, value, modifiers);
       // component v-model doesn't need extra runtime
       return false
     } else if (tag === 'select') {
       genSelect(el, value, modifiers);
     } else if (tag === 'input' && type === 'checkbox') {
       genCheckboxModel(el, value, modifiers);
     } else if (tag === 'input' && type === 'radio') {
       genRadioModel(el, value, modifiers);
     } else if (tag === 'input' || tag === 'textarea') {
       genDefaultModel(el, value, modifiers);
     } else if (!config.isReservedTag(tag)) {
       genComponentModel(el, value, modifiers);
       // component v-model doesn't need extra runtime
       return false
     } else {
       warn$1(
         "<" + (el.tag) + " v-model=\"" + value + "\">: " +
         "v-model is not supported on this element type. " +
         'If you are working with contenteditable, it\'s recommended to ' +
         'wrap a library dedicated for that purpose inside a custom component.',
         el.rawAttrsMap['v-model']
       );
     }
 
     // ensure runtime directive metadata
     return true
   }
 
   function genCheckboxModel (
     el,
     value,
     modifiers
   ) {
     var number = modifiers && modifiers.number;
     var valueBinding = getBindingAttr(el, 'value') || 'null';
     var trueValueBinding = getBindingAttr(el, 'true-value') || 'true';
     var falseValueBinding = getBindingAttr(el, 'false-value') || 'false';
     addProp(el, 'checked',
       "Array.isArray(" + value + ")" +
       "?_i(" + value + "," + valueBinding + ")>-1" + (
         trueValueBinding === 'true'
           ? (":(" + value + ")")
           : (":_q(" + value + "," + trueValueBinding + ")")
       )
     );
     addHandler(el, 'change',
       "var $$a=" + value + "," +
           '$$el=$event.target,' +
           "$$c=$$el.checked?(" + trueValueBinding + "):(" + falseValueBinding + ");" +
       'if(Array.isArray($$a)){' +
         "var $$v=" + (number ? '_n(' + valueBinding + ')' : valueBinding) + "," +
             '$$i=_i($$a,$$v);' +
         "if($$el.checked){$$i<0&&(" + (genAssignmentCode(value, '$$a.concat([$$v])')) + ")}" +
         "else{$$i>-1&&(" + (genAssignmentCode(value, '$$a.slice(0,$$i).concat($$a.slice($$i+1))')) + ")}" +
       "}else{" + (genAssignmentCode(value, '$$c')) + "}",
       null, true
     );
   }
 
   function genRadioModel (
     el,
     value,
     modifiers
   ) {
     var number = modifiers && modifiers.number;
     var valueBinding = getBindingAttr(el, 'value') || 'null';
     valueBinding = number ? ("_n(" + valueBinding + ")") : valueBinding;
     addProp(el, 'checked', ("_q(" + value + "," + valueBinding + ")"));
     addHandler(el, 'change', genAssignmentCode(value, valueBinding), null, true);
   }
 
   function genSelect (
     el,
     value,
     modifiers
   ) {
     var number = modifiers && modifiers.number;
     var selectedVal = "Array.prototype.filter" +
       ".call($event.target.options,function(o){return o.selected})" +
       ".map(function(o){var val = \"_value\" in o ? o._value : o.value;" +
       "return " + (number ? '_n(val)' : 'val') + "})";
 
     var assignment = '$event.target.multiple ? $$selectedVal : $$selectedVal[0]';
     var code = "var $$selectedVal = " + selectedVal + ";";
     code = code + " " + (genAssignmentCode(value, assignment));
     addHandler(el, 'change', code, null, true);
   }
 
   function genDefaultModel (
     el,
     value,
     modifiers
   ) {
     var type = el.attrsMap.type;
 
     // warn if v-bind:value conflicts with v-model
     // except for inputs with v-bind:type
     {
       var value$1 = el.attrsMap['v-bind:value'] || el.attrsMap[':value'];
       var typeBinding = el.attrsMap['v-bind:type'] || el.attrsMap[':type'];
       if (value$1 && !typeBinding) {
         var binding = el.attrsMap['v-bind:value'] ? 'v-bind:value' : ':value';
         warn$1(
           binding + "=\"" + value$1 + "\" conflicts with v-model on the same element " +
           'because the latter already expands to a value binding internally',
           el.rawAttrsMap[binding]
         );
       }
     }
 
     var ref = modifiers || {};
     var lazy = ref.lazy;
     var number = ref.number;
     var trim = ref.trim;
     var needCompositionGuard = !lazy && type !== 'range';
     var event = lazy
       ? 'change'
       : type === 'range'
         ? RANGE_TOKEN
         : 'input';
 
     var valueExpression = '$event.target.value';
     if (trim) {
       valueExpression = "$event.target.value.trim()";
     }
     if (number) {
       valueExpression = "_n(" + valueExpression + ")";
     }
 
     var code = genAssignmentCode(value, valueExpression);
     if (needCompositionGuard) {
       code = "if($event.target.composing)return;" + code;
     }
 
     addProp(el, 'value', ("(" + value + ")"));
     addHandler(el, event, code, null, true);
     if (trim || number) {
       addHandler(el, 'blur', '$forceUpdate()');
     }
   }
 
   /*  */
 
   // normalize v-model event tokens that can only be determined at runtime.
   // it's important to place the event as the first in the array because
   // the whole point is ensuring the v-model callback gets called before
   // user-attached handlers.
   function normalizeEvents (on) {
     /* istanbul ignore if */
     if (isDef(on[RANGE_TOKEN])) {
       // IE input[type=range] only supports `change` event
       var event = isIE ? 'change' : 'input';
       on[event] = [].concat(on[RANGE_TOKEN], on[event] || []);
       delete on[RANGE_TOKEN];
     }
     // This was originally intended to fix #4521 but no longer necessary
     // after 2.5. Keeping it for backwards compat with generated code from < 2.4
     /* istanbul ignore if */
     if (isDef(on[CHECKBOX_RADIO_TOKEN])) {
       on.change = [].concat(on[CHECKBOX_RADIO_TOKEN], on.change || []);
       delete on[CHECKBOX_RADIO_TOKEN];
     }
   }
 
   var target$1;
 
   function createOnceHandler$1 (event, handler, capture) {
     var _target = target$1; // save current target element in closure
     return function onceHandler () {
       var res = handler.apply(null, arguments);
       if (res !== null) {
         remove$2(event, onceHandler, capture, _target);
       }
     }
   }
 
   // #9446: Firefox <= 53 (in particular, ESR 52) has incorrect Event.timeStamp
   // implementation and does not fire microtasks in between event propagation, so
   // safe to exclude.
   var useMicrotaskFix = isUsingMicroTask && !(isFF && Number(isFF[1]) <= 53);
 
   function add$1 (
     name,
     handler,
     capture,
     passive
   ) {
     // async edge case #6566: inner click event triggers patch, event handler
     // attached to outer element during patch, and triggered again. This
     // happens because browsers fire microtask ticks between event propagation.
     // the solution is simple: we save the timestamp when a handler is attached,
     // and the handler would only fire if the event passed to it was fired
     // AFTER it was attached.
     if (useMicrotaskFix) {
       var attachedTimestamp = currentFlushTimestamp;
       var original = handler;
       handler = original._wrapper = function (e) {
         if (
           // no bubbling, should always fire.
           // this is just a safety net in case event.timeStamp is unreliable in
           // certain weird environments...
           e.target === e.currentTarget ||
           // event is fired after handler attachment
           e.timeStamp >= attachedTimestamp ||
           // bail for environments that have buggy event.timeStamp implementations
           // #9462 iOS 9 bug: event.timeStamp is 0 after history.pushState
           // #9681 QtWebEngine event.timeStamp is negative value
           e.timeStamp <= 0 ||
           // #9448 bail if event is fired in another document in a multi-page
           // electron/nw.js app, since event.timeStamp will be using a different
           // starting reference
           e.target.ownerDocument !== document
         ) {
           return original.apply(this, arguments)
         }
       };
     }
     target$1.addEventListener(
       name,
       handler,
       supportsPassive
         ? { capture: capture, passive: passive }
         : capture
     );
   }
 
   function remove$2 (
     name,
     handler,
     capture,
     _target
   ) {
     (_target || target$1).removeEventListener(
       name,
       handler._wrapper || handler,
       capture
     );
   }
 
   function updateDOMListeners (oldVnode, vnode) {
     if (isUndef(oldVnode.data.on) && isUndef(vnode.data.on)) {
       return
     }
     var on = vnode.data.on || {};
     var oldOn = oldVnode.data.on || {};
     target$1 = vnode.elm;
     normalizeEvents(on);
     updateListeners(on, oldOn, add$1, remove$2, createOnceHandler$1, vnode.context);
     target$1 = undefined;
   }
 
   var events = {
     create: updateDOMListeners,
     update: updateDOMListeners
   };
 
   /*  */
 
   var svgContainer;
 
   function updateDOMProps (oldVnode, vnode) {
     if (isUndef(oldVnode.data.domProps) && isUndef(vnode.data.domProps)) {
       return
     }
     var key, cur;
     var elm = vnode.elm;
     var oldProps = oldVnode.data.domProps || {};
     var props = vnode.data.domProps || {};
     // clone observed objects, as the user probably wants to mutate it
     if (isDef(props.__ob__)) {
       props = vnode.data.domProps = extend({}, props);
     }
 
     for (key in oldProps) {
       if (!(key in props)) {
         elm[key] = '';
       }
     }
 
     for (key in props) {
       cur = props[key];
       // ignore children if the node has textContent or innerHTML,
       // as these will throw away existing DOM nodes and cause removal errors
       // on subsequent patches (#3360)
       if (key === 'textContent' || key === 'innerHTML') {
         if (vnode.children) { vnode.children.length = 0; }
         if (cur === oldProps[key]) { continue }
         // #6601 work around Chrome version <= 55 bug where single textNode
         // replaced by innerHTML/textContent retains its parentNode property
         if (elm.childNodes.length === 1) {
           elm.removeChild(elm.childNodes[0]);
         }
       }
 
       if (key === 'value' && elm.tagName !== 'PROGRESS') {
         // store value as _value as well since
         // non-string values will be stringified
         elm._value = cur;
         // avoid resetting cursor position when value is the same
         var strCur = isUndef(cur) ? '' : String(cur);
         if (shouldUpdateValue(elm, strCur)) {
           elm.value = strCur;
         }
       } else if (key === 'innerHTML' && isSVG(elm.tagName) && isUndef(elm.innerHTML)) {
         // IE doesn't support innerHTML for SVG elements
         svgContainer = svgContainer || document.createElement('div');
         svgContainer.innerHTML = "<svg>" + cur + "</svg>";
         var svg = svgContainer.firstChild;
         while (elm.firstChild) {
           elm.removeChild(elm.firstChild);
         }
         while (svg.firstChild) {
           elm.appendChild(svg.firstChild);
         }
       } else if (
         // skip the update if old and new VDOM state is the same.
         // `value` is handled separately because the DOM value may be temporarily
         // out of sync with VDOM state due to focus, composition and modifiers.
         // This  #4521 by skipping the unnecessary `checked` update.
         cur !== oldProps[key]
       ) {
         // some property updates can throw
         // e.g. `value` on <progress> w/ non-finite value
         try {
           elm[key] = cur;
         } catch (e) {}
       }
     }
   }
 
   // check platforms/web/util/attrs.js acceptValue
 
 
   function shouldUpdateValue (elm, checkVal) {
     return (!elm.composing && (
       elm.tagName === 'OPTION' ||
       isNotInFocusAndDirty(elm, checkVal) ||
       isDirtyWithModifiers(elm, checkVal)
     ))
   }
 
   function isNotInFocusAndDirty (elm, checkVal) {
     // return true when textbox (.number and .trim) loses focus and its value is
     // not equal to the updated value
     var notInFocus = true;
     // #6157
     // work around IE bug when accessing document.activeElement in an iframe
     try { notInFocus = document.activeElement !== elm; } catch (e) {}
     return notInFocus && elm.value !== checkVal
   }
 
   function isDirtyWithModifiers (elm, newVal) {
     var value = elm.value;
     var modifiers = elm._vModifiers; // injected by v-model runtime
     if (isDef(modifiers)) {
       if (modifiers.number) {
         return toNumber(value) !== toNumber(newVal)
       }
       if (modifiers.trim) {
         return value.trim() !== newVal.trim()
       }
     }
     return value !== newVal
   }
 
   var domProps = {
     create: updateDOMProps,
     update: updateDOMProps
   };
 
   /*  */
 
   var parseStyleText = cached(function (cssText) {
     var res = {};
     var listDelimiter = /;(?![^(]*\))/g;
     var propertyDelimiter = /:(.+)/;
     cssText.split(listDelimiter).forEach(function (item) {
       if (item) {
         var tmp = item.split(propertyDelimiter);
         tmp.length > 1 && (res[tmp[0].trim()] = tmp[1].trim());
       }
     });
     return res
   });
 
   // merge static and dynamic style data on the same vnode
   function normalizeStyleData (data) {
     var style = normalizeStyleBinding(data.style);
     // static style is pre-processed into an object during compilation
     // and is always a fresh object, so it's safe to merge into it
     return data.staticStyle
       ? extend(data.staticStyle, style)
       : style
   }
 
   // normalize possible array / string values into Object
   function normalizeStyleBinding (bindingStyle) {
     if (Array.isArray(bindingStyle)) {
       return toObject(bindingStyle)
     }
     if (typeof bindingStyle === 'string') {
       return parseStyleText(bindingStyle)
     }
     return bindingStyle
   }
 
   /**
    * parent component style should be after child's
    * so that parent component's style could override it
    */
   function getStyle (vnode, checkChild) {
     var res = {};
     var styleData;
 
     if (checkChild) {
       var childNode = vnode;
       while (childNode.componentInstance) {
         childNode = childNode.componentInstance._vnode;
         if (
           childNode && childNode.data &&
           (styleData = normalizeStyleData(childNode.data))
         ) {
           extend(res, styleData);
         }
       }
     }
 
     if ((styleData = normalizeStyleData(vnode.data))) {
       extend(res, styleData);
     }
 
     var parentNode = vnode;
     while ((parentNode = parentNode.parent)) {
       if (parentNode.data && (styleData = normalizeStyleData(parentNode.data))) {
         extend(res, styleData);
       }
     }
     return res
   }
 
   /*  */
 
   var cssVarRE = /^--/;
   var importantRE = /\s*!important$/;
   var setProp = function (el, name, val) {
     /* istanbul ignore if */
     if (cssVarRE.test(name)) {
       el.style.setProperty(name, val);
     } else if (importantRE.test(val)) {
       el.style.setProperty(hyphenate(name), val.replace(importantRE, ''), 'important');
     } else {
       var normalizedName = normalize(name);
       if (Array.isArray(val)) {
         // Support values array created by autoprefixer, e.g.
         // {display: ["-webkit-box", "-ms-flexbox", "flex"]}
         // Set them one by one, and the browser will only set those it can recognize
         for (var i = 0, len = val.length; i < len; i++) {
           el.style[normalizedName] = val[i];
         }
       } else {
         el.style[normalizedName] = val;
       }
     }
   };
 
   var vendorNames = ['Webkit', 'Moz', 'ms'];
 
   var emptyStyle;
   var normalize = cached(function (prop) {
     emptyStyle = emptyStyle || document.createElement('div').style;
     prop = camelize(prop);
     if (prop !== 'filter' && (prop in emptyStyle)) {
       return prop
     }
     var capName = prop.charAt(0).toUpperCase() + prop.slice(1);
     for (var i = 0; i < vendorNames.length; i++) {
       var name = vendorNames[i] + capName;
       if (name in emptyStyle) {
         return name
       }
     }
   });
 
   function updateStyle (oldVnode, vnode) {
     var data = vnode.data;
     var oldData = oldVnode.data;
 
     if (isUndef(data.staticStyle) && isUndef(data.style) &&
       isUndef(oldData.staticStyle) && isUndef(oldData.style)
     ) {
       return
     }
 
     var cur, name;
     var el = vnode.elm;
     var oldStaticStyle = oldData.staticStyle;
     var oldStyleBinding = oldData.normalizedStyle || oldData.style || {};
 
     // if static style exists, stylebinding already merged into it when doing normalizeStyleData
     var oldStyle = oldStaticStyle || oldStyleBinding;
 
     var style = normalizeStyleBinding(vnode.data.style) || {};
 
     // store normalized style under a different key for next diff
     // make sure to clone it if it's reactive, since the user likely wants
     // to mutate it.
     vnode.data.normalizedStyle = isDef(style.__ob__)
       ? extend({}, style)
       : style;
 
     var newStyle = getStyle(vnode, true);
 
     for (name in oldStyle) {
       if (isUndef(newStyle[name])) {
         setProp(el, name, '');
       }
     }
     for (name in newStyle) {
       cur = newStyle[name];
       if (cur !== oldStyle[name]) {
         // ie9 setting to null has no effect, must use empty string
         setProp(el, name, cur == null ? '' : cur);
       }
     }
   }
 
   var style = {
     create: updateStyle,
     update: updateStyle
   };
 
   /*  */
 
   var whitespaceRE = /\s+/;
 
   /**
    * Add class with compatibility for SVG since classList is not supported on
    * SVG elements in IE
    */
   function addClass (el, cls) {
     /* istanbul ignore if */
     if (!cls || !(cls = cls.trim())) {
       return
     }
 
     /* istanbul ignore else */
     if (el.classList) {
       if (cls.indexOf(' ') > -1) {
         cls.split(whitespaceRE).forEach(function (c) { return el.classList.add(c); });
       } else {
         el.classList.add(cls);
       }
     } else {
       var cur = " " + (el.getAttribute('class') || '') + " ";
       if (cur.indexOf(' ' + cls + ' ') < 0) {
         el.setAttribute('class', (cur + cls).trim());
       }
     }
   }
 
   /**
    * Remove class with compatibility for SVG since classList is not supported on
    * SVG elements in IE
    */
   function removeClass (el, cls) {
     /* istanbul ignore if */
     if (!cls || !(cls = cls.trim())) {
       return
     }
 
     /* istanbul ignore else */
     if (el.classList) {
       if (cls.indexOf(' ') > -1) {
         cls.split(whitespaceRE).forEach(function (c) { return el.classList.remove(c); });
       } else {
         el.classList.remove(cls);
       }
       if (!el.classList.length) {
         el.removeAttribute('class');
       }
     } else {
       var cur = " " + (el.getAttribute('class') || '') + " ";
       var tar = ' ' + cls + ' ';
       while (cur.indexOf(tar) >= 0) {
         cur = cur.replace(tar, ' ');
       }
       cur = cur.trim();
       if (cur) {
         el.setAttribute('class', cur);
       } else {
         el.removeAttribute('class');
       }
     }
   }
 
   /*  */
 
   function resolveTransition (def$$1) {
     if (!def$$1) {
       return
     }
     /* istanbul ignore else */
     if (typeof def$$1 === 'object') {
       var res = {};
       if (def$$1.css !== false) {
         extend(res, autoCssTransition(def$$1.name || 'v'));
       }
       extend(res, def$$1);
       return res
     } else if (typeof def$$1 === 'string') {
       return autoCssTransition(def$$1)
     }
   }
 
   var autoCssTransition = cached(function (name) {
     return {
       enterClass: (name + "-enter"),
       enterToClass: (name + "-enter-to"),
       enterActiveClass: (name + "-enter-active"),
       leaveClass: (name + "-leave"),
       leaveToClass: (name + "-leave-to"),
       leaveActiveClass: (name + "-leave-active")
     }
   });
 
   var hasTransition = inBrowser && !isIE9;
   var TRANSITION = 'transition';
   var ANIMATION = 'animation';
 
   // Transition property/event sniffing
   var transitionProp = 'transition';
   var transitionEndEvent = 'transitionend';
   var animationProp = 'animation';
   var animationEndEvent = 'animationend';
   if (hasTransition) {
     /* istanbul ignore if */
     if (window.ontransitionend === undefined &&
       window.onwebkittransitionend !== undefined
     ) {
       transitionProp = 'WebkitTransition';
       transitionEndEvent = 'webkitTransitionEnd';
     }
     if (window.onanimationend === undefined &&
       window.onwebkitanimationend !== undefined
     ) {
       animationProp = 'WebkitAnimation';
       animationEndEvent = 'webkitAnimationEnd';
     }
   }
 
   // binding to window is necessary to make hot reload work in IE in strict mode
   var raf = inBrowser
     ? window.requestAnimationFrame
       ? window.requestAnimationFrame.bind(window)
       : setTimeout
     : /* istanbul ignore next */ function (fn) { return fn(); };
 
   function nextFrame (fn) {
     raf(function () {
       raf(fn);
     });
   }
 
   function addTransitionClass (el, cls) {
     var transitionClasses = el._transitionClasses || (el._transitionClasses = []);
     if (transitionClasses.indexOf(cls) < 0) {
       transitionClasses.push(cls);
       addClass(el, cls);
     }
   }
 
   function removeTransitionClass (el, cls) {
     if (el._transitionClasses) {
       remove(el._transitionClasses, cls);
     }
     removeClass(el, cls);
   }
 
   function whenTransitionEnds (
     el,
     expectedType,
     cb
   ) {
     var ref = getTransitionInfo(el, expectedType);
     var type = ref.type;
     var timeout = ref.timeout;
     var propCount = ref.propCount;
     if (!type) { return cb() }
     var event = type === TRANSITION ? transitionEndEvent : animationEndEvent;
     var ended = 0;
     var end = function () {
       el.removeEventListener(event, onEnd);
       cb();
     };
     var onEnd = function (e) {
       if (e.target === el) {
         if (++ended >= propCount) {
           end();
         }
       }
     };
     setTimeout(function () {
       if (ended < propCount) {
         end();
       }
     }, timeout + 1);
     el.addEventListener(event, onEnd);
   }
 
   var transformRE = /\b(transform|all)(,|$)/;
 
   function getTransitionInfo (el, expectedType) {
     var styles = window.getComputedStyle(el);
     // JSDOM may return undefined for transition properties
     var transitionDelays = (styles[transitionProp + 'Delay'] || '').split(', ');
     var transitionDurations = (styles[transitionProp + 'Duration'] || '').split(', ');
     var transitionTimeout = getTimeout(transitionDelays, transitionDurations);
     var animationDelays = (styles[animationProp + 'Delay'] || '').split(', ');
     var animationDurations = (styles[animationProp + 'Duration'] || '').split(', ');
     var animationTimeout = getTimeout(animationDelays, animationDurations);
 
     var type;
     var timeout = 0;
     var propCount = 0;
     /* istanbul ignore if */
     if (expectedType === TRANSITION) {
       if (transitionTimeout > 0) {
         type = TRANSITION;
         timeout = transitionTimeout;
         propCount = transitionDurations.length;
       }
     } else if (expectedType === ANIMATION) {
       if (animationTimeout > 0) {
         type = ANIMATION;
         timeout = animationTimeout;
         propCount = animationDurations.length;
       }
     } else {
       timeout = Math.max(transitionTimeout, animationTimeout);
       type = timeout > 0
         ? transitionTimeout > animationTimeout
           ? TRANSITION
           : ANIMATION
         : null;
       propCount = type
         ? type === TRANSITION
           ? transitionDurations.length
           : animationDurations.length
         : 0;
     }
     var hasTransform =
       type === TRANSITION &&
       transformRE.test(styles[transitionProp + 'Property']);
     return {
       type: type,
       timeout: timeout,
       propCount: propCount,
       hasTransform: hasTransform
     }
   }
 
   function getTimeout (delays, durations) {
     /* istanbul ignore next */
     while (delays.length < durations.length) {
       delays = delays.concat(delays);
     }
 
     return Math.max.apply(null, durations.map(function (d, i) {
       return toMs(d) + toMs(delays[i])
     }))
   }
 
   // Old versions of Chromium (below 61.0.3163.100) formats floating pointer numbers
   // in a locale-dependent way, using a comma instead of a dot.
   // If comma is not replaced with a dot, the input will be rounded down (i.e. acting
   // as a floor function) causing unexpected behaviors
   function toMs (s) {
     return Number(s.slice(0, -1).replace(',', '.')) * 1000
   }
 
   /*  */
 
   function enter (vnode, toggleDisplay) {
     var el = vnode.elm;
 
     // call leave callback now
     if (isDef(el._leaveCb)) {
       el._leaveCb.cancelled = true;
       el._leaveCb();
     }
 
     var data = resolveTransition(vnode.data.transition);
     if (isUndef(data)) {
       return
     }
 
     /* istanbul ignore if */
     if (isDef(el._enterCb) || el.nodeType !== 1) {
       return
     }
 
     var css = data.css;
     var type = data.type;
     var enterClass = data.enterClass;
     var enterToClass = data.enterToClass;
     var enterActiveClass = data.enterActiveClass;
     var appearClass = data.appearClass;
     var appearToClass = data.appearToClass;
     var appearActiveClass = data.appearActiveClass;
     var beforeEnter = data.beforeEnter;
     var enter = data.enter;
     var afterEnter = data.afterEnter;
     var enterCancelled = data.enterCancelled;
     var beforeAppear = data.beforeAppear;
     var appear = data.appear;
     var afterAppear = data.afterAppear;
     var appearCancelled = data.appearCancelled;
     var duration = data.duration;
 
     // activeInstance will always be the <transition> component managing this
     // transition. One edge case to check is when the <transition> is placed
     // as the root node of a child component. In that case we need to check
     // <transition>'s parent for appear check.
     var context = activeInstance;
     var transitionNode = activeInstance.$vnode;
     while (transitionNode && transitionNode.parent) {
       context = transitionNode.context;
       transitionNode = transitionNode.parent;
     }
 
     var isAppear = !context._isMounted || !vnode.isRootInsert;
 
     if (isAppear && !appear && appear !== '') {
       return
     }
 
     var startClass = isAppear && appearClass
       ? appearClass
       : enterClass;
     var activeClass = isAppear && appearActiveClass
       ? appearActiveClass
       : enterActiveClass;
     var toClass = isAppear && appearToClass
       ? appearToClass
       : enterToClass;
 
     var beforeEnterHook = isAppear
       ? (beforeAppear || beforeEnter)
       : beforeEnter;
     var enterHook = isAppear
       ? (typeof appear === 'function' ? appear : enter)
       : enter;
     var afterEnterHook = isAppear
       ? (afterAppear || afterEnter)
       : afterEnter;
     var enterCancelledHook = isAppear
       ? (appearCancelled || enterCancelled)
       : enterCancelled;
 
     var explicitEnterDuration = toNumber(
       isObject(duration)
         ? duration.enter
         : duration
     );
 
     if (explicitEnterDuration != null) {
       checkDuration(explicitEnterDuration, 'enter', vnode);
     }
 
     var expectsCSS = css !== false && !isIE9;
     var userWantsControl = getHookArgumentsLength(enterHook);
 
     var cb = el._enterCb = once(function () {
       if (expectsCSS) {
         removeTransitionClass(el, toClass);
         removeTransitionClass(el, activeClass);
       }
       if (cb.cancelled) {
         if (expectsCSS) {
           removeTransitionClass(el, startClass);
         }
         enterCancelledHook && enterCancelledHook(el);
       } else {
         afterEnterHook && afterEnterHook(el);
       }
       el._enterCb = null;
     });
 
     if (!vnode.data.show) {
       // remove pending leave element on enter by injecting an insert hook
       mergeVNodeHook(vnode, 'insert', function () {
         var parent = el.parentNode;
         var pendingNode = parent && parent._pending && parent._pending[vnode.key];
         if (pendingNode &&
           pendingNode.tag === vnode.tag &&
           pendingNode.elm._leaveCb
         ) {
           pendingNode.elm._leaveCb();
         }
         enterHook && enterHook(el, cb);
       });
     }
 
     // start enter transition
     beforeEnterHook && beforeEnterHook(el);
     if (expectsCSS) {
       addTransitionClass(el, startClass);
       addTransitionClass(el, activeClass);
       nextFrame(function () {
         removeTransitionClass(el, startClass);
         if (!cb.cancelled) {
           addTransitionClass(el, toClass);
           if (!userWantsControl) {
             if (isValidDuration(explicitEnterDuration)) {
               setTimeout(cb, explicitEnterDuration);
             } else {
               whenTransitionEnds(el, type, cb);
             }
           }
         }
       });
     }
 
     if (vnode.data.show) {
       toggleDisplay && toggleDisplay();
       enterHook && enterHook(el, cb);
     }
 
     if (!expectsCSS && !userWantsControl) {
       cb();
     }
   }
 
   function leave (vnode, rm) {
     var el = vnode.elm;
 
     // call enter callback now
     if (isDef(el._enterCb)) {
       el._enterCb.cancelled = true;
       el._enterCb();
     }
 
     var data = resolveTransition(vnode.data.transition);
     if (isUndef(data) || el.nodeType !== 1) {
       return rm()
     }
 
     /* istanbul ignore if */
     if (isDef(el._leaveCb)) {
       return
     }
 
     var css = data.css;
     var type = data.type;
     var leaveClass = data.leaveClass;
     var leaveToClass = data.leaveToClass;
     var leaveActiveClass = data.leaveActiveClass;
     var beforeLeave = data.beforeLeave;
     var leave = data.leave;
     var afterLeave = data.afterLeave;
     var leaveCancelled = data.leaveCancelled;
     var delayLeave = data.delayLeave;
     var duration = data.duration;
 
     var expectsCSS = css !== false && !isIE9;
     var userWantsControl = getHookArgumentsLength(leave);
 
     var explicitLeaveDuration = toNumber(
       isObject(duration)
         ? duration.leave
         : duration
     );
 
     if (isDef(explicitLeaveDuration)) {
       checkDuration(explicitLeaveDuration, 'leave', vnode);
     }
 
     var cb = el._leaveCb = once(function () {
       if (el.parentNode && el.parentNode._pending) {
         el.parentNode._pending[vnode.key] = null;
       }
       if (expectsCSS) {
         removeTransitionClass(el, leaveToClass);
         removeTransitionClass(el, leaveActiveClass);
       }
       if (cb.cancelled) {
         if (expectsCSS) {
           removeTransitionClass(el, leaveClass);
         }
         leaveCancelled && leaveCancelled(el);
       } else {
         rm();
         afterLeave && afterLeave(el);
       }
       el._leaveCb = null;
     });
 
     if (delayLeave) {
       delayLeave(performLeave);
     } else {
       performLeave();
     }
 
     function performLeave () {
       // the delayed leave may have already been cancelled
       if (cb.cancelled) {
         return
       }
       // record leaving element
       if (!vnode.data.show && el.parentNode) {
         (el.parentNode._pending || (el.parentNode._pending = {}))[(vnode.key)] = vnode;
       }
       beforeLeave && beforeLeave(el);
       if (expectsCSS) {
         addTransitionClass(el, leaveClass);
         addTransitionClass(el, leaveActiveClass);
         nextFrame(function () {
           removeTransitionClass(el, leaveClass);
           if (!cb.cancelled) {
             addTransitionClass(el, leaveToClass);
             if (!userWantsControl) {
               if (isValidDuration(explicitLeaveDuration)) {
                 setTimeout(cb, explicitLeaveDuration);
               } else {
                 whenTransitionEnds(el, type, cb);
               }
             }
           }
         });
       }
       leave && leave(el, cb);
       if (!expectsCSS && !userWantsControl) {
         cb();
       }
     }
   }
 
   // only used in dev mode
   function checkDuration (val, name, vnode) {
     if (typeof val !== 'number') {
       warn(
         "<transition> explicit " + name + " duration is not a valid number - " +
         "got " + (JSON.stringify(val)) + ".",
         vnode.context
       );
     } else if (isNaN(val)) {
       warn(
         "<transition> explicit " + name + " duration is NaN - " +
         'the duration expression might be incorrect.',
         vnode.context
       );
     }
   }
 
   function isValidDuration (val) {
     return typeof val === 'number' && !isNaN(val)
   }
 
   /**
    * Normalize a transition hook's argument length. The hook may be:
    * - a merged hook (invoker) with the original in .fns
    * - a wrapped component method (check ._length)
    * - a plain function (.length)
    */
   function getHookArgumentsLength (fn) {
     if (isUndef(fn)) {
       return false
     }
     var invokerFns = fn.fns;
     if (isDef(invokerFns)) {
       // invoker
       return getHookArgumentsLength(
         Array.isArray(invokerFns)
           ? invokerFns[0]
           : invokerFns
       )
     } else {
       return (fn._length || fn.length) > 1
     }
   }
 
   function _enter (_, vnode) {
     if (vnode.data.show !== true) {
       enter(vnode);
     }
   }
 
   var transition = inBrowser ? {
     create: _enter,
     activate: _enter,
     remove: function remove$$1 (vnode, rm) {
       /* istanbul ignore else */
       if (vnode.data.show !== true) {
         leave(vnode, rm);
       } else {
         rm();
       }
     }
   } : {};
 
   var platformModules = [
     attrs,
     klass,
     events,
     domProps,
     style,
     transition
   ];
 
   /*  */
 
   // the directive module should be applied last, after all
   // built-in modules have been applied.
   var modules = platformModules.concat(baseModules);
 
   var patch = createPatchFunction({ nodeOps: nodeOps, modules: modules });
 
   /**
    * Not type checking this file because flow doesn't like attaching
    * properties to Elements.
    */
 
   /* istanbul ignore if */
   if (isIE9) {
     // http://www.matts411.com/post/internet-explorer-9-oninput/
     document.addEventListener('selectionchange', function () {
       var el = document.activeElement;
       if (el && el.vmodel) {
         trigger(el, 'input');
       }
     });
   }
 
   var directive = {
     inserted: function inserted (el, binding, vnode, oldVnode) {
       if (vnode.tag === 'select') {
         // #6903
         if (oldVnode.elm && !oldVnode.elm._vOptions) {
           mergeVNodeHook(vnode, 'postpatch', function () {
             directive.componentUpdated(el, binding, vnode);
           });
         } else {
           setSelected(el, binding, vnode.context);
         }
         el._vOptions = [].map.call(el.options, getValue);
       } else if (vnode.tag === 'textarea' || isTextInputType(el.type)) {
         el._vModifiers = binding.modifiers;
         if (!binding.modifiers.lazy) {
           el.addEventListener('compositionstart', onCompositionStart);
           el.addEventListener('compositionend', onCompositionEnd);
           // Safari < 10.2 & UIWebView doesn't fire compositionend when
           // switching focus before confirming composition choice
           // this also fixes the issue where some browsers e.g. iOS Chrome
           // fires "change" instead of "input" on autocomplete.
           el.addEventListener('change', onCompositionEnd);
           /* istanbul ignore if */
           if (isIE9) {
             el.vmodel = true;
           }
         }
       }
     },
 
     componentUpdated: function componentUpdated (el, binding, vnode) {
       if (vnode.tag === 'select') {
         setSelected(el, binding, vnode.context);
         // in case the options rendered by v-for have changed,
         // it's possible that the value is out-of-sync with the rendered options.
         // detect such cases and filter out values that no longer has a matching
         // option in the DOM.
         var prevOptions = el._vOptions;
         var curOptions = el._vOptions = [].map.call(el.options, getValue);
         if (curOptions.some(function (o, i) { return !looseEqual(o, prevOptions[i]); })) {
           // trigger change event if
           // no matching option found for at least one value
           var needReset = el.multiple
             ? binding.value.some(function (v) { return hasNoMatchingOption(v, curOptions); })
             : binding.value !== binding.oldValue && hasNoMatchingOption(binding.value, curOptions);
           if (needReset) {
             trigger(el, 'change');
           }
         }
       }
     }
   };
 
   function setSelected (el, binding, vm) {
     actuallySetSelected(el, binding, vm);
     /* istanbul ignore if */
     if (isIE || isEdge) {
       setTimeout(function () {
         actuallySetSelected(el, binding, vm);
       }, 0);
     }
   }
 
   function actuallySetSelected (el, binding, vm) {
     var value = binding.value;
     var isMultiple = el.multiple;
     if (isMultiple && !Array.isArray(value)) {
       warn(
         "<select multiple v-model=\"" + (binding.expression) + "\"> " +
         "expects an Array value for its binding, but got " + (Object.prototype.toString.call(value).slice(8, -1)),
         vm
       );
       return
     }
     var selected, option;
     for (var i = 0, l = el.options.length; i < l; i++) {
       option = el.options[i];
       if (isMultiple) {
         selected = looseIndexOf(value, getValue(option)) > -1;
         if (option.selected !== selected) {
           option.selected = selected;
         }
       } else {
         if (looseEqual(getValue(option), value)) {
           if (el.selectedIndex !== i) {
             el.selectedIndex = i;
           }
           return
         }
       }
     }
     if (!isMultiple) {
       el.selectedIndex = -1;
     }
   }
 
   function hasNoMatchingOption (value, options) {
     return options.every(function (o) { return !looseEqual(o, value); })
   }
 
   function getValue (option) {
     return '_value' in option
       ? option._value
       : option.value
   }
 
   function onCompositionStart (e) {
     e.target.composing = true;
   }
 
   function onCompositionEnd (e) {
     // prevent triggering an input event for no reason
     if (!e.target.composing) { return }
     e.target.composing = false;
     trigger(e.target, 'input');
   }
 
   function trigger (el, type) {
     var e = document.createEvent('HTMLEvents');
     e.initEvent(type, true, true);
     el.dispatchEvent(e);
   }
 
   /*  */
 
   // recursively search for possible transition defined inside the component root
   function locateNode (vnode) {
     return vnode.componentInstance && (!vnode.data || !vnode.data.transition)
       ? locateNode(vnode.componentInstance._vnode)
       : vnode
   }
 
   var show = {
     bind: function bind (el, ref, vnode) {
       var value = ref.value;
 
       vnode = locateNode(vnode);
       var transition$$1 = vnode.data && vnode.data.transition;
       var originalDisplay = el.__vOriginalDisplay =
         el.style.display === 'none' ? '' : el.style.display;
       if (value && transition$$1) {
         vnode.data.show = true;
         enter(vnode, function () {
           el.style.display = originalDisplay;
         });
       } else {
         el.style.display = value ? originalDisplay : 'none';
       }
     },
 
     update: function update (el, ref, vnode) {
       var value = ref.value;
       var oldValue = ref.oldValue;
 
       /* istanbul ignore if */
       if (!value === !oldValue) { return }
       vnode = locateNode(vnode);
       var transition$$1 = vnode.data && vnode.data.transition;
       if (transition$$1) {
         vnode.data.show = true;
         if (value) {
           enter(vnode, function () {
             el.style.display = el.__vOriginalDisplay;
           });
         } else {
           leave(vnode, function () {
             el.style.display = 'none';
           });
         }
       } else {
         el.style.display = value ? el.__vOriginalDisplay : 'none';
       }
     },
 
     unbind: function unbind (
       el,
       binding,
       vnode,
       oldVnode,
       isDestroy
     ) {
       if (!isDestroy) {
         el.style.display = el.__vOriginalDisplay;
       }
     }
   };
 
   var platformDirectives = {
     model: directive,
     show: show
   };
 
   /*  */
 
   var transitionProps = {
     name: String,
     appear: Boolean,
     css: Boolean,
     mode: String,
     type: String,
     enterClass: String,
     leaveClass: String,
     enterToClass: String,
     leaveToClass: String,
     enterActiveClass: String,
     leaveActiveClass: String,
     appearClass: String,
     appearActiveClass: String,
     appearToClass: String,
     duration: [Number, String, Object]
   };
 
   // in case the child is also an abstract component, e.g. <keep-alive>
   // we want to recursively retrieve the real component to be rendered
   function getRealChild (vnode) {
     var compOptions = vnode && vnode.componentOptions;
     if (compOptions && compOptions.Ctor.options.abstract) {
       return getRealChild(getFirstComponentChild(compOptions.children))
     } else {
       return vnode
     }
   }
 
   function extractTransitionData (comp) {
     var data = {};
     var options = comp.$options;
     // props
     for (var key in options.propsData) {
       data[key] = comp[key];
     }
     // events.
     // extract listeners and pass them directly to the transition methods
     var listeners = options._parentListeners;
     for (var key$1 in listeners) {
       data[camelize(key$1)] = listeners[key$1];
     }
     return data
   }
 
   function placeholder (h, rawChild) {
     if (/\d-keep-alive$/.test(rawChild.tag)) {
       return h('keep-alive', {
         props: rawChild.componentOptions.propsData
       })
     }
   }
 
   function hasParentTransition (vnode) {
     while ((vnode = vnode.parent)) {
       if (vnode.data.transition) {
         return true
       }
     }
   }
 
   function isSameChild (child, oldChild) {
     return oldChild.key === child.key && oldChild.tag === child.tag
   }
 
   var isNotTextNode = function (c) { return c.tag || isAsyncPlaceholder(c); };
 
   var isVShowDirective = function (d) { return d.name === 'show'; };
 
   var Transition = {
     name: 'transition',
     props: transitionProps,
     abstract: true,
 
     render: function render (h) {
       var this$1 = this;
 
       var children = this.$slots.default;
       if (!children) {
         return
       }
 
       // filter out text nodes (possible whitespaces)
       children = children.filter(isNotTextNode);
       /* istanbul ignore if */
       if (!children.length) {
         return
       }
 
       // warn multiple elements
       if (children.length > 1) {
         warn(
           '<transition> can only be used on a single element. Use ' +
           '<transition-group> for lists.',
           this.$parent
         );
       }
 
       var mode = this.mode;
 
       // warn invalid mode
       if (mode && mode !== 'in-out' && mode !== 'out-in'
       ) {
         warn(
           'invalid <transition> mode: ' + mode,
           this.$parent
         );
       }
 
       var rawChild = children[0];
 
       // if this is a component root node and the component's
       // parent container node also has transition, skip.
       if (hasParentTransition(this.$vnode)) {
         return rawChild
       }
 
       // apply transition data to child
       // use getRealChild() to ignore abstract components e.g. keep-alive
       var child = getRealChild(rawChild);
       /* istanbul ignore if */
       if (!child) {
         return rawChild
       }
 
       if (this._leaving) {
         return placeholder(h, rawChild)
       }
 
       // ensure a key that is unique to the vnode type and to this transition
       // component instance. This key will be used to remove pending leaving nodes
       // during entering.
       var id = "__transition-" + (this._uid) + "-";
       child.key = child.key == null
         ? child.isComment
           ? id + 'comment'
           : id + child.tag
         : isPrimitive(child.key)
           ? (String(child.key).indexOf(id) === 0 ? child.key : id + child.key)
           : child.key;
 
       var data = (child.data || (child.data = {})).transition = extractTransitionData(this);
       var oldRawChild = this._vnode;
       var oldChild = getRealChild(oldRawChild);
 
       // mark v-show
       // so that the transition module can hand over the control to the directive
       if (child.data.directives && child.data.directives.some(isVShowDirective)) {
         child.data.show = true;
       }
 
       if (
         oldChild &&
         oldChild.data &&
         !isSameChild(child, oldChild) &&
         !isAsyncPlaceholder(oldChild) &&
         // #6687 component root is a comment node
         !(oldChild.componentInstance && oldChild.componentInstance._vnode.isComment)
       ) {
         // replace old child transition data with fresh one
         // important for dynamic transitions!
         var oldData = oldChild.data.transition = extend({}, data);
         // handle transition mode
         if (mode === 'out-in') {
           // return placeholder node and queue update when leave finishes
           this._leaving = true;
           mergeVNodeHook(oldData, 'afterLeave', function () {
             this$1._leaving = false;
             this$1.$forceUpdate();
           });
           return placeholder(h, rawChild)
         } else if (mode === 'in-out') {
           if (isAsyncPlaceholder(child)) {
             return oldRawChild
           }
           var delayedLeave;
           var performLeave = function () { delayedLeave(); };
           mergeVNodeHook(data, 'afterEnter', performLeave);
           mergeVNodeHook(data, 'enterCancelled', performLeave);
           mergeVNodeHook(oldData, 'delayLeave', function (leave) { delayedLeave = leave; });
         }
       }
 
       return rawChild
     }
   };
 
   /*  */
 
   var props = extend({
     tag: String,
     moveClass: String
   }, transitionProps);
 
   delete props.mode;
 
   var TransitionGroup = {
     props: props,
 
     beforeMount: function beforeMount () {
       var this$1 = this;
 
       var update = this._update;
       this._update = function (vnode, hydrating) {
         var restoreActiveInstance = setActiveInstance(this$1);
         // force removing pass
         this$1.__patch__(
           this$1._vnode,
           this$1.kept,
           false, // hydrating
           true // removeOnly (!important, avoids unnecessary moves)
         );
         this$1._vnode = this$1.kept;
         restoreActiveInstance();
         update.call(this$1, vnode, hydrating);
       };
     },
 
     render: function render (h) {
       var tag = this.tag || this.$vnode.data.tag || 'span';
       var map = Object.create(null);
       var prevChildren = this.prevChildren = this.children;
       var rawChildren = this.$slots.default || [];
       var children = this.children = [];
       var transitionData = extractTransitionData(this);
 
       for (var i = 0; i < rawChildren.length; i++) {
         var c = rawChildren[i];
         if (c.tag) {
           if (c.key != null && String(c.key).indexOf('__vlist') !== 0) {
             children.push(c);
             map[c.key] = c
             ;(c.data || (c.data = {})).transition = transitionData;
           } else {
             var opts = c.componentOptions;
             var name = opts ? (opts.Ctor.options.name || opts.tag || '') : c.tag;
             warn(("<transition-group> children must be keyed: <" + name + ">"));
           }
         }
       }
 
       if (prevChildren) {
         var kept = [];
         var removed = [];
         for (var i$1 = 0; i$1 < prevChildren.length; i$1++) {
           var c$1 = prevChildren[i$1];
           c$1.data.transition = transitionData;
           c$1.data.pos = c$1.elm.getBoundingClientRect();
           if (map[c$1.key]) {
             kept.push(c$1);
           } else {
             removed.push(c$1);
           }
         }
         this.kept = h(tag, null, kept);
         this.removed = removed;
       }
 
       return h(tag, null, children)
     },
 
     updated: function updated () {
       var children = this.prevChildren;
       var moveClass = this.moveClass || ((this.name || 'v') + '-move');
       if (!children.length || !this.hasMove(children[0].elm, moveClass)) {
         return
       }
 
       // we divide the work into three loops to avoid mixing DOM reads and writes
       // in each iteration - which helps prevent layout thrashing.
       children.forEach(callPendingCbs);
       children.forEach(recordPosition);
       children.forEach(applyTranslation);
 
       // force reflow to put everything in position
       // assign to this to avoid being removed in tree-shaking
       // $flow-disable-line
       this._reflow = document.body.offsetHeight;
 
       children.forEach(function (c) {
         if (c.data.moved) {
           var el = c.elm;
           var s = el.style;
           addTransitionClass(el, moveClass);
           s.transform = s.WebkitTransform = s.transitionDuration = '';
           el.addEventListener(transitionEndEvent, el._moveCb = function cb (e) {
             if (e && e.target !== el) {
               return
             }
             if (!e || /transform$/.test(e.propertyName)) {
               el.removeEventListener(transitionEndEvent, cb);
               el._moveCb = null;
               removeTransitionClass(el, moveClass);
             }
           });
         }
       });
     },
 
     methods: {
       hasMove: function hasMove (el, moveClass) {
         /* istanbul ignore if */
         if (!hasTransition) {
           return false
         }
         /* istanbul ignore if */
         if (this._hasMove) {
           return this._hasMove
         }
         // Detect whether an element with the move class applied has
         // CSS transitions. Since the element may be inside an entering
         // transition at this very moment, we make a clone of it and remove
         // all other transition classes applied to ensure only the move class
         // is applied.
         var clone = el.cloneNode();
         if (el._transitionClasses) {
           el._transitionClasses.forEach(function (cls) { removeClass(clone, cls); });
         }
         addClass(clone, moveClass);
         clone.style.display = 'none';
         this.$el.appendChild(clone);
         var info = getTransitionInfo(clone);
         this.$el.removeChild(clone);
         return (this._hasMove = info.hasTransform)
       }
     }
   };
 
   function callPendingCbs (c) {
     /* istanbul ignore if */
     if (c.elm._moveCb) {
       c.elm._moveCb();
     }
     /* istanbul ignore if */
     if (c.elm._enterCb) {
       c.elm._enterCb();
     }
   }
 
   function recordPosition (c) {
     c.data.newPos = c.elm.getBoundingClientRect();
   }
 
   function applyTranslation (c) {
     var oldPos = c.data.pos;
     var newPos = c.data.newPos;
     var dx = oldPos.left - newPos.left;
     var dy = oldPos.top - newPos.top;
     if (dx || dy) {
       c.data.moved = true;
       var s = c.elm.style;
       s.transform = s.WebkitTransform = "translate(" + dx + "px," + dy + "px)";
       s.transitionDuration = '0s';
     }
   }
 
   var platformComponents = {
     Transition: Transition,
     TransitionGroup: TransitionGroup
   };
 
   /*  */
 
   // install platform specific utils
   Vue.config.mustUseProp = mustUseProp;
   Vue.config.isReservedTag = isReservedTag;
   Vue.config.isReservedAttr = isReservedAttr;
   Vue.config.getTagNamespace = getTagNamespace;
   Vue.config.isUnknownElement = isUnknownElement;
 
   // install platform runtime directives & components
   extend(Vue.options.directives, platformDirectives);
   extend(Vue.options.components, platformComponents);
 
   // install platform patch function
   Vue.prototype.__patch__ = inBrowser ? patch : noop;
 
   // public mount method
   Vue.prototype.$mount = function (
     el,
     hydrating
   ) {
     el = el && inBrowser ? query(el) : undefined;
     return mountComponent(this, el, hydrating)
   };
 
   // devtools global hook
   /* istanbul ignore next */
   if (inBrowser) {
     setTimeout(function () {
       if (config.devtools) {
         if (devtools) {
           devtools.emit('init', Vue);
         } else {
           console[console.info ? 'info' : 'log'](
             'Download the Vue Devtools extension for a better development experience:\n' +
             'https://github.com/vuejs/vue-devtools'
           );
         }
       }
       if (config.productionTip !== false &&
         typeof console !== 'undefined'
       ) {
         console[console.info ? 'info' : 'log'](
           "You are running Vue in development mode.\n" +
           "Make sure to turn on production mode when deploying for production.\n" +
           "See more tips at https://vuejs.org/guide/deployment.html"
         );
       }
     }, 0);
   }
 
   /*  */
 
   var defaultTagRE = /\{\{((?:.|\r?\n)+?)\}\}/g;
   var regexEscapeRE = /[-.*+?^${}()|[\]\/\\]/g;
 
   var buildRegex = cached(function (delimiters) {
     var open = delimiters[0].replace(regexEscapeRE, '\\$&');
     var close = delimiters[1].replace(regexEscapeRE, '\\$&');
     return new RegExp(open + '((?:.|\\n)+?)' + close, 'g')
   });
 
 
 
   function parseText (
     text,
     delimiters
   ) {
     var tagRE = delimiters ? buildRegex(delimiters) : defaultTagRE;
     if (!tagRE.test(text)) {
       return
     }
     var tokens = [];
     var rawTokens = [];
     var lastIndex = tagRE.lastIndex = 0;
     var match, index, tokenValue;
     while ((match = tagRE.exec(text))) {
       index = match.index;
       // push text token
       if (index > lastIndex) {
         rawTokens.push(tokenValue = text.slice(lastIndex, index));
         tokens.push(JSON.stringify(tokenValue));
       }
       // tag token
       var exp = parseFilters(match[1].trim());
       tokens.push(("_s(" + exp + ")"));
       rawTokens.push({ '@binding': exp });
       lastIndex = index + match[0].length;
     }
     if (lastIndex < text.length) {
       rawTokens.push(tokenValue = text.slice(lastIndex));
       tokens.push(JSON.stringify(tokenValue));
     }
     return {
       expression: tokens.join('+'),
       tokens: rawTokens
     }
   }
 
   /*  */
 
   function transformNode (el, options) {
     var warn = options.warn || baseWarn;
     var staticClass = getAndRemoveAttr(el, 'class');
     if (staticClass) {
       var res = parseText(staticClass, options.delimiters);
       if (res) {
         warn(
           "class=\"" + staticClass + "\": " +
           'Interpolation inside attributes has been removed. ' +
           'Use v-bind or the colon shorthand instead. For example, ' +
           'instead of <div class="{{ val }}">, use <div :class="val">.',
           el.rawAttrsMap['class']
         );
       }
     }
     if (staticClass) {
       el.staticClass = JSON.stringify(staticClass);
     }
     var classBinding = getBindingAttr(el, 'class', false /* getStatic */);
     if (classBinding) {
       el.classBinding = classBinding;
     }
   }
 
   function genData (el) {
     var data = '';
     if (el.staticClass) {
       data += "staticClass:" + (el.staticClass) + ",";
     }
     if (el.classBinding) {
       data += "class:" + (el.classBinding) + ",";
     }
     return data
   }
 
   var klass$1 = {
     staticKeys: ['staticClass'],
     transformNode: transformNode,
     genData: genData
   };
 
   /*  */
 
   function transformNode$1 (el, options) {
     var warn = options.warn || baseWarn;
     var staticStyle = getAndRemoveAttr(el, 'style');
     if (staticStyle) {
       /* istanbul ignore if */
       {
         var res = parseText(staticStyle, options.delimiters);
         if (res) {
           warn(
             "style=\"" + staticStyle + "\": " +
             'Interpolation inside attributes has been removed. ' +
             'Use v-bind or the colon shorthand instead. For example, ' +
             'instead of <div style="{{ val }}">, use <div :style="val">.',
             el.rawAttrsMap['style']
           );
         }
       }
       el.staticStyle = JSON.stringify(parseStyleText(staticStyle));
     }
 
     var styleBinding = getBindingAttr(el, 'style', false /* getStatic */);
     if (styleBinding) {
       el.styleBinding = styleBinding;
     }
   }
 
   function genData$1 (el) {
     var data = '';
     if (el.staticStyle) {
       data += "staticStyle:" + (el.staticStyle) + ",";
     }
     if (el.styleBinding) {
       data += "style:(" + (el.styleBinding) + "),";
     }
     return data
   }
 
   var style$1 = {
     staticKeys: ['staticStyle'],
     transformNode: transformNode$1,
     genData: genData$1
   };
 
   /*  */
 
   var decoder;
 
   var he = {
     decode: function decode (html) {
       decoder = decoder || document.createElement('div');
       decoder.innerHTML = html;
       return decoder.textContent
     }
   };
 
   /*  */
 
   var isUnaryTag = makeMap(
     'area,base,br,col,embed,frame,hr,img,input,isindex,keygen,' +
     'link,meta,param,source,track,wbr'
   );
 
   // Elements that you can, intentionally, leave open
   // (and which close themselves)
   var canBeLeftOpenTag = makeMap(
     'colgroup,dd,dt,li,options,p,td,tfoot,th,thead,tr,source'
   );
 
   // HTML5 tags https://html.spec.whatwg.org/multipage/indices.html#elements-3
   // Phrasing Content https://html.spec.whatwg.org/multipage/dom.html#phrasing-content
   var isNonPhrasingTag = makeMap(
     'address,article,aside,base,blockquote,body,caption,col,colgroup,dd,' +
     'details,dialog,div,dl,dt,fieldset,figcaption,figure,footer,form,' +
     'h1,h2,h3,h4,h5,h6,head,header,hgroup,hr,html,legend,li,menuitem,meta,' +
     'optgroup,option,param,rp,rt,source,style,summary,tbody,td,tfoot,th,thead,' +
     'title,tr,track'
   );
 
   /**
    * Not type-checking this file because it's mostly vendor code.
    */
 
   // Regular Expressions for parsing tags and attributes
   var attribute = /^\s*([^\s"'<>\/=]+)(?:\s*(=)\s*(?:"([^"]*)"+|'([^']*)'+|([^\s"'=<>`]+)))?/;
   var dynamicArgAttribute = /^\s*((?:v-[\w-]+:|@|:|#)\[[^=]+\][^\s"'<>\/=]*)(?:\s*(=)\s*(?:"([^"]*)"+|'([^']*)'+|([^\s"'=<>`]+)))?/;
   var ncname = "[a-zA-Z_][\\-\\.0-9_a-zA-Z" + (unicodeRegExp.source) + "]*";
   var qnameCapture = "((?:" + ncname + "\\:)?" + ncname + ")";
   var startTagOpen = new RegExp(("^<" + qnameCapture));
   var startTagClose = /^\s*(\/?)>/;
   var endTag = new RegExp(("^<\\/" + qnameCapture + "[^>]*>"));
   var doctype = /^<!DOCTYPE [^>]+>/i;
   // #7298: escape - to avoid being passed as HTML comment when inlined in page
   var comment = /^<!\--/;
   var conditionalComment = /^<!\[/;
 
   // Special Elements (can contain anything)
   var isPlainTextElement = makeMap('script,style,textarea', true);
   var reCache = {};
 
   var decodingMap = {
     '&lt;': '<',
     '&gt;': '>',
     '&quot;': '"',
     '&amp;': '&',
     '&#10;': '\n',
     '&#9;': '\t',
     '&#39;': "'"
   };
   var encodedAttr = /&(?:lt|gt|quot|amp|#39);/g;
   var encodedAttrWithNewLines = /&(?:lt|gt|quot|amp|#39|#10|#9);/g;
 
   // #5992
   var isIgnoreNewlineTag = makeMap('pre,textarea', true);
   var shouldIgnoreFirstNewline = function (tag, html) { return tag && isIgnoreNewlineTag(tag) && html[0] === '\n'; };
 
   function decodeAttr (value, shouldDecodeNewlines) {
     var re = shouldDecodeNewlines ? encodedAttrWithNewLines : encodedAttr;
     return value.replace(re, function (match) { return decodingMap[match]; })
   }
 
   function parseHTML (html, options) {
     var stack = [];
     var expectHTML = options.expectHTML;
     var isUnaryTag$$1 = options.isUnaryTag || no;
     var canBeLeftOpenTag$$1 = options.canBeLeftOpenTag || no;
     var index = 0;
     var last, lastTag;
     while (html) {
       last = html;
       // Make sure we're not in a plaintext content element like script/style
       if (!lastTag || !isPlainTextElement(lastTag)) {
         var textEnd = html.indexOf('<');
         if (textEnd === 0) {
           // Comment:
           if (comment.test(html)) {
             var commentEnd = html.indexOf('-->');
 
             if (commentEnd >= 0) {
               if (options.shouldKeepComment) {
                 options.comment(html.substring(4, commentEnd), index, index + commentEnd + 3);
               }
               advance(commentEnd + 3);
               continue
             }
           }
 
           // http://en.wikipedia.org/wiki/Conditional_comment#Downlevel-revealed_conditional_comment
           if (conditionalComment.test(html)) {
             var conditionalEnd = html.indexOf(']>');
 
             if (conditionalEnd >= 0) {
               advance(conditionalEnd + 2);
               continue
             }
           }
 
           // Doctype:
           var doctypeMatch = html.match(doctype);
           if (doctypeMatch) {
             advance(doctypeMatch[0].length);
             continue
           }
 
           // End tag:
           var endTagMatch = html.match(endTag);
           if (endTagMatch) {
             var curIndex = index;
             advance(endTagMatch[0].length);
             parseEndTag(endTagMatch[1], curIndex, index);
             continue
           }
 
           // Start tag:
           var startTagMatch = parseStartTag();
           if (startTagMatch) {
             handleStartTag(startTagMatch);
             if (shouldIgnoreFirstNewline(startTagMatch.tagName, html)) {
               advance(1);
             }
             continue
           }
         }
 
         var text = (void 0), rest = (void 0), next = (void 0);
         if (textEnd >= 0) {
           rest = html.slice(textEnd);
           while (
             !endTag.test(rest) &&
             !startTagOpen.test(rest) &&
             !comment.test(rest) &&
             !conditionalComment.test(rest)
           ) {
             // < in plain text, be forgiving and treat it as text
             next = rest.indexOf('<', 1);
             if (next < 0) { break }
             textEnd += next;
             rest = html.slice(textEnd);
           }
           text = html.substring(0, textEnd);
         }
 
         if (textEnd < 0) {
           text = html;
         }
 
         if (text) {
           advance(text.length);
         }
 
         if (options.chars && text) {
           options.chars(text, index - text.length, index);
         }
       } else {
         var endTagLength = 0;
         var stackedTag = lastTag.toLowerCase();
         var reStackedTag = reCache[stackedTag] || (reCache[stackedTag] = new RegExp('([\\s\\S]*?)(</' + stackedTag + '[^>]*>)', 'i'));
         var rest$1 = html.replace(reStackedTag, function (all, text, endTag) {
           endTagLength = endTag.length;
           if (!isPlainTextElement(stackedTag) && stackedTag !== 'noscript') {
             text = text
               .replace(/<!\--([\s\S]*?)-->/g, '$1') // #7298
               .replace(/<!\[CDATA\[([\s\S]*?)]]>/g, '$1');
           }
           if (shouldIgnoreFirstNewline(stackedTag, text)) {
             text = text.slice(1);
           }
           if (options.chars) {
             options.chars(text);
           }
           return ''
         });
         index += html.length - rest$1.length;
         html = rest$1;
         parseEndTag(stackedTag, index - endTagLength, index);
       }
 
       if (html === last) {
         options.chars && options.chars(html);
         if (!stack.length && options.warn) {
           options.warn(("Mal-formatted tag at end of template: \"" + html + "\""), { start: index + html.length });
         }
         break
       }
     }
 
     // Clean up any remaining tags
     parseEndTag();
 
     function advance (n) {
       index += n;
       html = html.substring(n);
     }
 
     function parseStartTag () {
       var start = html.match(startTagOpen);
       if (start) {
         var match = {
           tagName: start[1],
           attrs: [],
           start: index
         };
         advance(start[0].length);
         var end, attr;
         while (!(end = html.match(startTagClose)) && (attr = html.match(dynamicArgAttribute) || html.match(attribute))) {
           attr.start = index;
           advance(attr[0].length);
           attr.end = index;
           match.attrs.push(attr);
         }
         if (end) {
           match.unarySlash = end[1];
           advance(end[0].length);
           match.end = index;
           return match
         }
       }
     }
 
     function handleStartTag (match) {
       var tagName = match.tagName;
       var unarySlash = match.unarySlash;
 
       if (expectHTML) {
         if (lastTag === 'p' && isNonPhrasingTag(tagName)) {
           parseEndTag(lastTag);
         }
         if (canBeLeftOpenTag$$1(tagName) && lastTag === tagName) {
           parseEndTag(tagName);
         }
       }
 
       var unary = isUnaryTag$$1(tagName) || !!unarySlash;
 
       var l = match.attrs.length;
       var attrs = new Array(l);
       for (var i = 0; i < l; i++) {
         var args = match.attrs[i];
         var value = args[3] || args[4] || args[5] || '';
         var shouldDecodeNewlines = tagName === 'a' && args[1] === 'href'
           ? options.shouldDecodeNewlinesForHref
           : options.shouldDecodeNewlines;
         attrs[i] = {
           name: args[1],
           value: decodeAttr(value, shouldDecodeNewlines)
         };
         if (options.outputSourceRange) {
           attrs[i].start = args.start + args[0].match(/^\s*/).length;
           attrs[i].end = args.end;
         }
       }
 
       if (!unary) {
         stack.push({ tag: tagName, lowerCasedTag: tagName.toLowerCase(), attrs: attrs, start: match.start, end: match.end });
         lastTag = tagName;
       }
 
       if (options.start) {
         options.start(tagName, attrs, unary, match.start, match.end);
       }
     }
 
     function parseEndTag (tagName, start, end) {
       var pos, lowerCasedTagName;
       if (start == null) { start = index; }
       if (end == null) { end = index; }
 
       // Find the closest opened tag of the same type
       if (tagName) {
         lowerCasedTagName = tagName.toLowerCase();
         for (pos = stack.length - 1; pos >= 0; pos--) {
           if (stack[pos].lowerCasedTag === lowerCasedTagName) {
             break
           }
         }
       } else {
         // If no tag name is provided, clean shop
         pos = 0;
       }
 
       if (pos >= 0) {
         // Close all the open elements, up the stack
         for (var i = stack.length - 1; i >= pos; i--) {
           if (i > pos || !tagName &&
             options.warn
           ) {
             options.warn(
               ("tag <" + (stack[i].tag) + "> has no matching end tag."),
               { start: stack[i].start, end: stack[i].end }
             );
           }
           if (options.end) {
             options.end(stack[i].tag, start, end);
           }
         }
 
         // Remove the open elements from the stack
         stack.length = pos;
         lastTag = pos && stack[pos - 1].tag;
       } else if (lowerCasedTagName === 'br') {
         if (options.start) {
           options.start(tagName, [], true, start, end);
         }
       } else if (lowerCasedTagName === 'p') {
         if (options.start) {
           options.start(tagName, [], false, start, end);
         }
         if (options.end) {
           options.end(tagName, start, end);
         }
       }
     }
   }
 
   /*  */
 
   var onRE = /^@|^v-on:/;
   var dirRE = /^v-|^@|^:|^#/;
   var forAliasRE = /([\s\S]*?)\s+(?:in|of)\s+([\s\S]*)/;
   var forIteratorRE = /,([^,\}\]]*)(?:,([^,\}\]]*))?$/;
   var stripParensRE = /^\(|\)$/g;
   var dynamicArgRE = /^\[.*\]$/;
 
   var argRE = /:(.*)$/;
   var bindRE = /^:|^\.|^v-bind:/;
   var modifierRE = /\.[^.\]]+(?=[^\]]*$)/g;
 
   var slotRE = /^v-slot(:|$)|^#/;
 
   var lineBreakRE = /[\r\n]/;
   var whitespaceRE$1 = /\s+/g;
 
   var invalidAttributeRE = /[\s"'<>\/=]/;
 
   var decodeHTMLCached = cached(he.decode);
 
   var emptySlotScopeToken = "_empty_";
 
   // configurable state
   var warn$2;
   var delimiters;
   var transforms;
   var preTransforms;
   var postTransforms;
   var platformIsPreTag;
   var platformMustUseProp;
   var platformGetTagNamespace;
   var maybeComponent;
 
   function createASTElement (
     tag,
     attrs,
     parent
   ) {
     return {
       type: 1,
       tag: tag,
       attrsList: attrs,
       attrsMap: makeAttrsMap(attrs),
       rawAttrsMap: {},
       parent: parent,
       children: []
     }
   }
 
   /**
    * Convert HTML string to AST.
    */
   function parse (
     template,
     options
   ) {
     warn$2 = options.warn || baseWarn;
 
     platformIsPreTag = options.isPreTag || no;
     platformMustUseProp = options.mustUseProp || no;
     platformGetTagNamespace = options.getTagNamespace || no;
     var isReservedTag = options.isReservedTag || no;
     maybeComponent = function (el) { return !!el.component || !isReservedTag(el.tag); };
 
     transforms = pluckModuleFunction(options.modules, 'transformNode');
     preTransforms = pluckModuleFunction(options.modules, 'preTransformNode');
     postTransforms = pluckModuleFunction(options.modules, 'postTransformNode');
 
     delimiters = options.delimiters;
 
     var stack = [];
     var preserveWhitespace = options.preserveWhitespace !== false;
     var whitespaceOption = options.whitespace;
     var root;
     var currentParent;
     var inVPre = false;
     var inPre = false;
     var warned = false;
 
     function warnOnce (msg, range) {
       if (!warned) {
         warned = true;
         warn$2(msg, range);
       }
     }
 
     function closeElement (element) {
       trimEndingWhitespace(element);
       if (!inVPre && !element.processed) {
         element = processElement(element, options);
       }
       // tree management
       if (!stack.length && element !== root) {
         // allow root elements with v-if, v-else-if and v-else
         if (root.if && (element.elseif || element.else)) {
           {
             checkRootConstraints(element);
           }
           addIfCondition(root, {
             exp: element.elseif,
             block: element
           });
         } else {
           warnOnce(
             "Component template should contain exactly one root element. " +
             "If you are using v-if on multiple elements, " +
             "use v-else-if to chain them instead.",
             { start: element.start }
           );
         }
       }
       if (currentParent && !element.forbidden) {
         if (element.elseif || element.else) {
           processIfConditions(element, currentParent);
         } else {
           if (element.slotScope) {
             // scoped slot
             // keep it in the children list so that v-else(-if) conditions can
             // find it as the prev node.
             var name = element.slotTarget || '"default"'
             ;(currentParent.scopedSlots || (currentParent.scopedSlots = {}))[name] = element;
           }
           currentParent.children.push(element);
           element.parent = currentParent;
         }
       }
 
       // final children cleanup
       // filter out scoped slots
       element.children = element.children.filter(function (c) { return !(c).slotScope; });
       // remove trailing whitespace node again
       trimEndingWhitespace(element);
 
       // check pre state
       if (element.pre) {
         inVPre = false;
       }
       if (platformIsPreTag(element.tag)) {
         inPre = false;
       }
       // apply post-transforms
       for (var i = 0; i < postTransforms.length; i++) {
         postTransforms[i](element, options);
       }
     }
 
     function trimEndingWhitespace (el) {
       // remove trailing whitespace node
       if (!inPre) {
         var lastNode;
         while (
           (lastNode = el.children[el.children.length - 1]) &&
           lastNode.type === 3 &&
           lastNode.text === ' '
         ) {
           el.children.pop();
         }
       }
     }
 
     function checkRootConstraints (el) {
       if (el.tag === 'slot' || el.tag === 'template') {
         warnOnce(
           "Cannot use <" + (el.tag) + "> as component root element because it may " +
           'contain multiple nodes.',
           { start: el.start }
         );
       }
       if (el.attrsMap.hasOwnProperty('v-for')) {
         warnOnce(
           'Cannot use v-for on stateful component root element because ' +
           'it renders multiple elements.',
           el.rawAttrsMap['v-for']
         );
       }
     }
 
     parseHTML(template, {
       warn: warn$2,
       expectHTML: options.expectHTML,
       isUnaryTag: options.isUnaryTag,
       canBeLeftOpenTag: options.canBeLeftOpenTag,
       shouldDecodeNewlines: options.shouldDecodeNewlines,
       shouldDecodeNewlinesForHref: options.shouldDecodeNewlinesForHref,
       shouldKeepComment: options.comments,
       outputSourceRange: options.outputSourceRange,
       start: function start (tag, attrs, unary, start$1, end) {
         // check namespace.
         // inherit parent ns if there is one
         var ns = (currentParent && currentParent.ns) || platformGetTagNamespace(tag);
 
         // handle IE svg bug
         /* istanbul ignore if */
         if (isIE && ns === 'svg') {
           attrs = guardIESVGBug(attrs);
         }
 
         var element = createASTElement(tag, attrs, currentParent);
         if (ns) {
           element.ns = ns;
         }
 
         {
           if (options.outputSourceRange) {
             element.start = start$1;
             element.end = end;
             element.rawAttrsMap = element.attrsList.reduce(function (cumulated, attr) {
               cumulated[attr.name] = attr;
               return cumulated
             }, {});
           }
           attrs.forEach(function (attr) {
             if (invalidAttributeRE.test(attr.name)) {
               warn$2(
                 "Invalid dynamic argument expression: attribute names cannot contain " +
                 "spaces, quotes, <, >, / or =.",
                 {
                   start: attr.start + attr.name.indexOf("["),
                   end: attr.start + attr.name.length
                 }
               );
             }
           });
         }
 
         if (isForbiddenTag(element) && !isServerRendering()) {
           element.forbidden = true;
           warn$2(
             'Templates should only be responsible for mapping the state to the ' +
             'UI. Avoid placing tags with side-effects in your templates, such as ' +
             "<" + tag + ">" + ', as they will not be parsed.',
             { start: element.start }
           );
         }
 
         // apply pre-transforms
         for (var i = 0; i < preTransforms.length; i++) {
           element = preTransforms[i](element, options) || element;
         }
 
         if (!inVPre) {
           processPre(element);
           if (element.pre) {
             inVPre = true;
           }
         }
         if (platformIsPreTag(element.tag)) {
           inPre = true;
         }
         if (inVPre) {
           processRawAttrs(element);
         } else if (!element.processed) {
           // structural directives
           processFor(element);
           processIf(element);
           processOnce(element);
         }
 
         if (!root) {
           root = element;
           {
             checkRootConstraints(root);
           }
         }
 
         if (!unary) {
           currentParent = element;
           stack.push(element);
         } else {
           closeElement(element);
         }
       },
 
       end: function end (tag, start, end$1) {
         var element = stack[stack.length - 1];
         // pop stack
         stack.length -= 1;
         currentParent = stack[stack.length - 1];
         if (options.outputSourceRange) {
           element.end = end$1;
         }
         closeElement(element);
       },
 
       chars: function chars (text, start, end) {
         if (!currentParent) {
           {
             if (text === template) {
               warnOnce(
                 'Component template requires a root element, rather than just text.',
                 { start: start }
               );
             } else if ((text = text.trim())) {
               warnOnce(
                 ("text \"" + text + "\" outside root element will be ignored."),
                 { start: start }
               );
             }
           }
           return
         }
         // IE textarea placeholder bug
         /* istanbul ignore if */
         if (isIE &&
           currentParent.tag === 'textarea' &&
           currentParent.attrsMap.placeholder === text
         ) {
           return
         }
         var children = currentParent.children;
         if (inPre || text.trim()) {
           text = isTextTag(currentParent) ? text : decodeHTMLCached(text);
         } else if (!children.length) {
           // remove the whitespace-only node right after an opening tag
           text = '';
         } else if (whitespaceOption) {
           if (whitespaceOption === 'condense') {
             // in condense mode, remove the whitespace node if it contains
             // line break, otherwise condense to a single space
             text = lineBreakRE.test(text) ? '' : ' ';
           } else {
             text = ' ';
           }
         } else {
           text = preserveWhitespace ? ' ' : '';
         }
         if (text) {
           if (!inPre && whitespaceOption === 'condense') {
             // condense consecutive whitespaces into single space
             text = text.replace(whitespaceRE$1, ' ');
           }
           var res;
           var child;
           if (!inVPre && text !== ' ' && (res = parseText(text, delimiters))) {
             child = {
               type: 2,
               expression: res.expression,
               tokens: res.tokens,
               text: text
             };
           } else if (text !== ' ' || !children.length || children[children.length - 1].text !== ' ') {
             child = {
               type: 3,
               text: text
             };
           }
           if (child) {
             if (options.outputSourceRange) {
               child.start = start;
               child.end = end;
             }
             children.push(child);
           }
         }
       },
       comment: function comment (text, start, end) {
         // adding anything as a sibling to the root node is forbidden
         // comments should still be allowed, but ignored
         if (currentParent) {
           var child = {
             type: 3,
             text: text,
             isComment: true
           };
           if (options.outputSourceRange) {
             child.start = start;
             child.end = end;
           }
           currentParent.children.push(child);
         }
       }
     });
     return root
   }
 
   function processPre (el) {
     if (getAndRemoveAttr(el, 'v-pre') != null) {
       el.pre = true;
     }
   }
 
   function processRawAttrs (el) {
     var list = el.attrsList;
     var len = list.length;
     if (len) {
       var attrs = el.attrs = new Array(len);
       for (var i = 0; i < len; i++) {
         attrs[i] = {
           name: list[i].name,
           value: JSON.stringify(list[i].value)
         };
         if (list[i].start != null) {
           attrs[i].start = list[i].start;
           attrs[i].end = list[i].end;
         }
       }
     } else if (!el.pre) {
       // non root node in pre blocks with no attributes
       el.plain = true;
     }
   }
 
   function processElement (
     element,
     options
   ) {
     processKey(element);
 
     // determine whether this is a plain element after
     // removing structural attributes
     element.plain = (
       !element.key &&
       !element.scopedSlots &&
       !element.attrsList.length
     );
 
     processRef(element);
     processSlotContent(element);
     processSlotOutlet(element);
     processComponent(element);
     for (var i = 0; i < transforms.length; i++) {
       element = transforms[i](element, options) || element;
     }
     processAttrs(element);
     return element
   }
 
   function processKey (el) {
     var exp = getBindingAttr(el, 'key');
     if (exp) {
       {
         if (el.tag === 'template') {
           warn$2(
             "<template> cannot be keyed. Place the key on real elements instead.",
             getRawBindingAttr(el, 'key')
           );
         }
         if (el.for) {
           var iterator = el.iterator2 || el.iterator1;
           var parent = el.parent;
           if (iterator && iterator === exp && parent && parent.tag === 'transition-group') {
             warn$2(
               "Do not use v-for index as key on <transition-group> children, " +
               "this is the same as not using keys.",
               getRawBindingAttr(el, 'key'),
               true /* tip */
             );
           }
         }
       }
       el.key = exp;
     }
   }
 
   function processRef (el) {
     var ref = getBindingAttr(el, 'ref');
     if (ref) {
       el.ref = ref;
       el.refInFor = checkInFor(el);
     }
   }
 
   function processFor (el) {
     var exp;
     if ((exp = getAndRemoveAttr(el, 'v-for'))) {
       var res = parseFor(exp);
       if (res) {
         extend(el, res);
       } else {
         warn$2(
           ("Invalid v-for expression: " + exp),
           el.rawAttrsMap['v-for']
         );
       }
     }
   }
 
 
 
   function parseFor (exp) {
     var inMatch = exp.match(forAliasRE);
     if (!inMatch) { return }
     var res = {};
     res.for = inMatch[2].trim();
     var alias = inMatch[1].trim().replace(stripParensRE, '');
     var iteratorMatch = alias.match(forIteratorRE);
     if (iteratorMatch) {
       res.alias = alias.replace(forIteratorRE, '').trim();
       res.iterator1 = iteratorMatch[1].trim();
       if (iteratorMatch[2]) {
         res.iterator2 = iteratorMatch[2].trim();
       }
     } else {
       res.alias = alias;
     }
     return res
   }
 
   function processIf (el) {
     var exp = getAndRemoveAttr(el, 'v-if');
     if (exp) {
       el.if = exp;
       addIfCondition(el, {
         exp: exp,
         block: el
       });
     } else {
       if (getAndRemoveAttr(el, 'v-else') != null) {
         el.else = true;
       }
       var elseif = getAndRemoveAttr(el, 'v-else-if');
       if (elseif) {
         el.elseif = elseif;
       }
     }
   }
 
   function processIfConditions (el, parent) {
     var prev = findPrevElement(parent.children);
     if (prev && prev.if) {
       addIfCondition(prev, {
         exp: el.elseif,
         block: el
       });
     } else {
       warn$2(
         "v-" + (el.elseif ? ('else-if="' + el.elseif + '"') : 'else') + " " +
         "used on element <" + (el.tag) + "> without corresponding v-if.",
         el.rawAttrsMap[el.elseif ? 'v-else-if' : 'v-else']
       );
     }
   }
 
   function findPrevElement (children) {
     var i = children.length;
     while (i--) {
       if (children[i].type === 1) {
         return children[i]
       } else {
         if (children[i].text !== ' ') {
           warn$2(
             "text \"" + (children[i].text.trim()) + "\" between v-if and v-else(-if) " +
             "will be ignored.",
             children[i]
           );
         }
         children.pop();
       }
     }
   }
 
   function addIfCondition (el, condition) {
     if (!el.ifConditions) {
       el.ifConditions = [];
     }
     el.ifConditions.push(condition);
   }
 
   function processOnce (el) {
     var once$$1 = getAndRemoveAttr(el, 'v-once');
     if (once$$1 != null) {
       el.once = true;
     }
   }
 
   // handle content being passed to a component as slot,
   // e.g. <template slot="xxx">, <div slot-scope="xxx">
   function processSlotContent (el) {
     var slotScope;
     if (el.tag === 'template') {
       slotScope = getAndRemoveAttr(el, 'scope');
       /* istanbul ignore if */
       if (slotScope) {
         warn$2(
           "the \"scope\" attribute for scoped slots have been deprecated and " +
           "replaced by \"slot-scope\" since 2.5. The new \"slot-scope\" attribute " +
           "can also be used on plain elements in addition to <template> to " +
           "denote scoped slots.",
           el.rawAttrsMap['scope'],
           true
         );
       }
       el.slotScope = slotScope || getAndRemoveAttr(el, 'slot-scope');
     } else if ((slotScope = getAndRemoveAttr(el, 'slot-scope'))) {
       /* istanbul ignore if */
       if (el.attrsMap['v-for']) {
         warn$2(
           "Ambiguous combined usage of slot-scope and v-for on <" + (el.tag) + "> " +
           "(v-for takes higher priority). Use a wrapper <template> for the " +
           "scoped slot to make it clearer.",
           el.rawAttrsMap['slot-scope'],
           true
         );
       }
       el.slotScope = slotScope;
     }
 
     // slot="xxx"
     var slotTarget = getBindingAttr(el, 'slot');
     if (slotTarget) {
       el.slotTarget = slotTarget === '""' ? '"default"' : slotTarget;
       el.slotTargetDynamic = !!(el.attrsMap[':slot'] || el.attrsMap['v-bind:slot']);
       // preserve slot as an attribute for native shadow DOM compat
       // only for non-scoped slots.
       if (el.tag !== 'template' && !el.slotScope) {
         addAttr(el, 'slot', slotTarget, getRawBindingAttr(el, 'slot'));
       }
     }
 
     // 2.6 v-slot syntax
     {
       if (el.tag === 'template') {
         // v-slot on <template>
         var slotBinding = getAndRemoveAttrByRegex(el, slotRE);
         if (slotBinding) {
           {
             if (el.slotTarget || el.slotScope) {
               warn$2(
                 "Unexpected mixed usage of different slot syntaxes.",
                 el
               );
             }
             if (el.parent && !maybeComponent(el.parent)) {
               warn$2(
                 "<template v-slot> can only appear at the root level inside " +
                 "the receiving component",
                 el
               );
             }
           }
           var ref = getSlotName(slotBinding);
           var name = ref.name;
           var dynamic = ref.dynamic;
           el.slotTarget = name;
           el.slotTargetDynamic = dynamic;
           el.slotScope = slotBinding.value || emptySlotScopeToken; // force it into a scoped slot for perf
         }
       } else {
         // v-slot on component, denotes default slot
         var slotBinding$1 = getAndRemoveAttrByRegex(el, slotRE);
         if (slotBinding$1) {
           {
             if (!maybeComponent(el)) {
               warn$2(
                 "v-slot can only be used on components or <template>.",
                 slotBinding$1
               );
             }
             if (el.slotScope || el.slotTarget) {
               warn$2(
                 "Unexpected mixed usage of different slot syntaxes.",
                 el
               );
             }
             if (el.scopedSlots) {
               warn$2(
                 "To avoid scope ambiguity, the default slot should also use " +
                 "<template> syntax when there are other named slots.",
                 slotBinding$1
               );
             }
           }
           // add the component's children to its default slot
           var slots = el.scopedSlots || (el.scopedSlots = {});
           var ref$1 = getSlotName(slotBinding$1);
           var name$1 = ref$1.name;
           var dynamic$1 = ref$1.dynamic;
           var slotContainer = slots[name$1] = createASTElement('template', [], el);
           slotContainer.slotTarget = name$1;
           slotContainer.slotTargetDynamic = dynamic$1;
           slotContainer.children = el.children.filter(function (c) {
             if (!c.slotScope) {
               c.parent = slotContainer;
               return true
             }
           });
           slotContainer.slotScope = slotBinding$1.value || emptySlotScopeToken;
           // remove children as they are returned from scopedSlots now
           el.children = [];
           // mark el non-plain so data gets generated
           el.plain = false;
         }
       }
     }
   }
 
   function getSlotName (binding) {
     var name = binding.name.replace(slotRE, '');
     if (!name) {
       if (binding.name[0] !== '#') {
         name = 'default';
       } else {
         warn$2(
           "v-slot shorthand syntax requires a slot name.",
           binding
         );
       }
     }
     return dynamicArgRE.test(name)
       // dynamic [name]
       ? { name: name.slice(1, -1), dynamic: true }
       // static name
       : { name: ("\"" + name + "\""), dynamic: false }
   }
 
   // handle <slot/> outlets
   function processSlotOutlet (el) {
     if (el.tag === 'slot') {
       el.slotName = getBindingAttr(el, 'name');
       if (el.key) {
         warn$2(
           "`key` does not work on <slot> because slots are abstract outlets " +
           "and can possibly expand into multiple elements. " +
           "Use the key on a wrapping element instead.",
           getRawBindingAttr(el, 'key')
         );
       }
     }
   }
 
   function processComponent (el) {
     var binding;
     if ((binding = getBindingAttr(el, 'is'))) {
       el.component = binding;
     }
     if (getAndRemoveAttr(el, 'inline-template') != null) {
       el.inlineTemplate = true;
     }
   }
 
   function processAttrs (el) {
     var list = el.attrsList;
     var i, l, name, rawName, value, modifiers, syncGen, isDynamic;
     for (i = 0, l = list.length; i < l; i++) {
       name = rawName = list[i].name;
       value = list[i].value;
       if (dirRE.test(name)) {
         // mark element as dynamic
         el.hasBindings = true;
         // modifiers
         modifiers = parseModifiers(name.replace(dirRE, ''));
         // support .foo shorthand syntax for the .prop modifier
         if (modifiers) {
           name = name.replace(modifierRE, '');
         }
         if (bindRE.test(name)) { // v-bind
           name = name.replace(bindRE, '');
           value = parseFilters(value);
           isDynamic = dynamicArgRE.test(name);
           if (isDynamic) {
             name = name.slice(1, -1);
           }
           if (
             value.trim().length === 0
           ) {
             warn$2(
               ("The value for a v-bind expression cannot be empty. Found in \"v-bind:" + name + "\"")
             );
           }
           if (modifiers) {
             if (modifiers.prop && !isDynamic) {
               name = camelize(name);
               if (name === 'innerHtml') { name = 'innerHTML'; }
             }
             if (modifiers.camel && !isDynamic) {
               name = camelize(name);
             }
             if (modifiers.sync) {
               syncGen = genAssignmentCode(value, "$event");
               if (!isDynamic) {
                 addHandler(
                   el,
                   ("update:" + (camelize(name))),
                   syncGen,
                   null,
                   false,
                   warn$2,
                   list[i]
                 );
                 if (hyphenate(name) !== camelize(name)) {
                   addHandler(
                     el,
                     ("update:" + (hyphenate(name))),
                     syncGen,
                     null,
                     false,
                     warn$2,
                     list[i]
                   );
                 }
               } else {
                 // handler w/ dynamic event name
                 addHandler(
                   el,
                   ("\"update:\"+(" + name + ")"),
                   syncGen,
                   null,
                   false,
                   warn$2,
                   list[i],
                   true // dynamic
                 );
               }
             }
           }
           if ((modifiers && modifiers.prop) || (
             !el.component && platformMustUseProp(el.tag, el.attrsMap.type, name)
           )) {
             addProp(el, name, value, list[i], isDynamic);
           } else {
             addAttr(el, name, value, list[i], isDynamic);
           }
         } else if (onRE.test(name)) { // v-on
           name = name.replace(onRE, '');
           isDynamic = dynamicArgRE.test(name);
           if (isDynamic) {
             name = name.slice(1, -1);
           }
           addHandler(el, name, value, modifiers, false, warn$2, list[i], isDynamic);
         } else { // normal directives
           name = name.replace(dirRE, '');
           // parse arg
           var argMatch = name.match(argRE);
           var arg = argMatch && argMatch[1];
           isDynamic = false;
           if (arg) {
             name = name.slice(0, -(arg.length + 1));
             if (dynamicArgRE.test(arg)) {
               arg = arg.slice(1, -1);
               isDynamic = true;
             }
           }
           addDirective(el, name, rawName, value, arg, isDynamic, modifiers, list[i]);
           if (name === 'model') {
             checkForAliasModel(el, value);
           }
         }
       } else {
         // literal attribute
         {
           var res = parseText(value, delimiters);
           if (res) {
             warn$2(
               name + "=\"" + value + "\": " +
               'Interpolation inside attributes has been removed. ' +
               'Use v-bind or the colon shorthand instead. For example, ' +
               'instead of <div id="{{ val }}">, use <div :id="val">.',
               list[i]
             );
           }
         }
         addAttr(el, name, JSON.stringify(value), list[i]);
         // #6887 firefox doesn't update muted state if set via attribute
         // even immediately after element creation
         if (!el.component &&
             name === 'muted' &&
             platformMustUseProp(el.tag, el.attrsMap.type, name)) {
           addProp(el, name, 'true', list[i]);
         }
       }
     }
   }
 
   function checkInFor (el) {
     var parent = el;
     while (parent) {
       if (parent.for !== undefined) {
         return true
       }
       parent = parent.parent;
     }
     return false
   }
 
   function parseModifiers (name) {
     var match = name.match(modifierRE);
     if (match) {
       var ret = {};
       match.forEach(function (m) { ret[m.slice(1)] = true; });
       return ret
     }
   }
 
   function makeAttrsMap (attrs) {
     var map = {};
     for (var i = 0, l = attrs.length; i < l; i++) {
       if (
         map[attrs[i].name] && !isIE && !isEdge
       ) {
         warn$2('duplicate attribute: ' + attrs[i].name, attrs[i]);
       }
       map[attrs[i].name] = attrs[i].value;
     }
     return map
   }
 
   // for script (e.g. type="x/template") or style, do not decode content
   function isTextTag (el) {
     return el.tag === 'script' || el.tag === 'style'
   }
 
   function isForbiddenTag (el) {
     return (
       el.tag === 'style' ||
       (el.tag === 'script' && (
         !el.attrsMap.type ||
         el.attrsMap.type === 'text/javascript'
       ))
     )
   }
 
   var ieNSBug = /^xmlns:NS\d+/;
   var ieNSPrefix = /^NS\d+:/;
 
   /* istanbul ignore next */
   function guardIESVGBug (attrs) {
     var res = [];
     for (var i = 0; i < attrs.length; i++) {
       var attr = attrs[i];
       if (!ieNSBug.test(attr.name)) {
         attr.name = attr.name.replace(ieNSPrefix, '');
         res.push(attr);
       }
     }
     return res
   }
 
   function checkForAliasModel (el, value) {
     var _el = el;
     while (_el) {
       if (_el.for && _el.alias === value) {
         warn$2(
           "<" + (el.tag) + " v-model=\"" + value + "\">: " +
           "You are binding v-model directly to a v-for iteration alias. " +
           "This will not be able to modify the v-for source array because " +
           "writing to the alias is like modifying a function local variable. " +
           "Consider using an array of objects and use v-model on an object property instead.",
           el.rawAttrsMap['v-model']
         );
       }
       _el = _el.parent;
     }
   }
 
   /*  */
 
   function preTransformNode (el, options) {
     if (el.tag === 'input') {
       var map = el.attrsMap;
       if (!map['v-model']) {
         return
       }
 
       var typeBinding;
       if (map[':type'] || map['v-bind:type']) {
         typeBinding = getBindingAttr(el, 'type');
       }
       if (!map.type && !typeBinding && map['v-bind']) {
         typeBinding = "(" + (map['v-bind']) + ").type";
       }
 
       if (typeBinding) {
         var ifCondition = getAndRemoveAttr(el, 'v-if', true);
         var ifConditionExtra = ifCondition ? ("&&(" + ifCondition + ")") : "";
         var hasElse = getAndRemoveAttr(el, 'v-else', true) != null;
         var elseIfCondition = getAndRemoveAttr(el, 'v-else-if', true);
         // 1. checkbox
         var branch0 = cloneASTElement(el);
         // process for on the main node
         processFor(branch0);
         addRawAttr(branch0, 'type', 'checkbox');
         processElement(branch0, options);
         branch0.processed = true; // prevent it from double-processed
         branch0.if = "(" + typeBinding + ")==='checkbox'" + ifConditionExtra;
         addIfCondition(branch0, {
           exp: branch0.if,
           block: branch0
         });
         // 2. add radio else-if condition
         var branch1 = cloneASTElement(el);
         getAndRemoveAttr(branch1, 'v-for', true);
         addRawAttr(branch1, 'type', 'radio');
         processElement(branch1, options);
         addIfCondition(branch0, {
           exp: "(" + typeBinding + ")==='radio'" + ifConditionExtra,
           block: branch1
         });
         // 3. other
         var branch2 = cloneASTElement(el);
         getAndRemoveAttr(branch2, 'v-for', true);
         addRawAttr(branch2, ':type', typeBinding);
         processElement(branch2, options);
         addIfCondition(branch0, {
           exp: ifCondition,
           block: branch2
         });
 
         if (hasElse) {
           branch0.else = true;
         } else if (elseIfCondition) {
           branch0.elseif = elseIfCondition;
         }
 
         return branch0
       }
     }
   }
 
   function cloneASTElement (el) {
     return createASTElement(el.tag, el.attrsList.slice(), el.parent)
   }
 
   var model$1 = {
     preTransformNode: preTransformNode
   };
 
   var modules$1 = [
     klass$1,
     style$1,
     model$1
   ];
 
   /*  */
 
   function text (el, dir) {
     if (dir.value) {
       addProp(el, 'textContent', ("_s(" + (dir.value) + ")"), dir);
     }
   }
 
   /*  */
 
   function html (el, dir) {
     if (dir.value) {
       addProp(el, 'innerHTML', ("_s(" + (dir.value) + ")"), dir);
     }
   }
 
   var directives$1 = {
     model: model,
     text: text,
     html: html
   };
 
   /*  */
 
   var baseOptions = {
     expectHTML: true,
     modules: modules$1,
     directives: directives$1,
     isPreTag: isPreTag,
     isUnaryTag: isUnaryTag,
     mustUseProp: mustUseProp,
     canBeLeftOpenTag: canBeLeftOpenTag,
     isReservedTag: isReservedTag,
     getTagNamespace: getTagNamespace,
     staticKeys: genStaticKeys(modules$1)
   };
 
   /*  */
 
   var isStaticKey;
   var isPlatformReservedTag;
 
   var genStaticKeysCached = cached(genStaticKeys$1);
 
   /**
    * Goal of the optimizer: walk the generated template AST tree
    * and detect sub-trees that are purely static, i.e. parts of
    * the DOM that never needs to change.
    *
    * Once we detect these sub-trees, we can:
    *
    * 1. Hoist them into constants, so that we no longer need to
    *    create fresh nodes for them on each re-render;
    * 2. Completely skip them in the patching process.
    */
   function optimize (root, options) {
     if (!root) { return }
     isStaticKey = genStaticKeysCached(options.staticKeys || '');
     isPlatformReservedTag = options.isReservedTag || no;
     // first pass: mark all non-static nodes.
     markStatic$1(root);
     // second pass: mark static roots.
     markStaticRoots(root, false);
   }
 
   function genStaticKeys$1 (keys) {
     return makeMap(
       'type,tag,attrsList,attrsMap,plain,parent,children,attrs,start,end,rawAttrsMap' +
       (keys ? ',' + keys : '')
     )
   }
 
   function markStatic$1 (node) {
     node.static = isStatic(node);
     if (node.type === 1) {
       // do not make component slot content static. this avoids
       // 1. components not able to mutate slot nodes
       // 2. static slot content fails for hot-reloading
       if (
         !isPlatformReservedTag(node.tag) &&
         node.tag !== 'slot' &&
         node.attrsMap['inline-template'] == null
       ) {
         return
       }
       for (var i = 0, l = node.children.length; i < l; i++) {
         var child = node.children[i];
         markStatic$1(child);
         if (!child.static) {
           node.static = false;
         }
       }
       if (node.ifConditions) {
         for (var i$1 = 1, l$1 = node.ifConditions.length; i$1 < l$1; i$1++) {
           var block = node.ifConditions[i$1].block;
           markStatic$1(block);
           if (!block.static) {
             node.static = false;
           }
         }
       }
     }
   }
 
   function markStaticRoots (node, isInFor) {
     if (node.type === 1) {
       if (node.static || node.once) {
         node.staticInFor = isInFor;
       }
       // For a node to qualify as a static root, it should have children that
       // are not just static text. Otherwise the cost of hoisting out will
       // outweigh the benefits and it's better off to just always render it fresh.
       if (node.static && node.children.length && !(
         node.children.length === 1 &&
         node.children[0].type === 3
       )) {
         node.staticRoot = true;
         return
       } else {
         node.staticRoot = false;
       }
       if (node.children) {
         for (var i = 0, l = node.children.length; i < l; i++) {
           markStaticRoots(node.children[i], isInFor || !!node.for);
         }
       }
       if (node.ifConditions) {
         for (var i$1 = 1, l$1 = node.ifConditions.length; i$1 < l$1; i$1++) {
           markStaticRoots(node.ifConditions[i$1].block, isInFor);
         }
       }
     }
   }
 
   function isStatic (node) {
     if (node.type === 2) { // expression
       return false
     }
     if (node.type === 3) { // text
       return true
     }
     return !!(node.pre || (
       !node.hasBindings && // no dynamic bindings
       !node.if && !node.for && // not v-if or v-for or v-else
       !isBuiltInTag(node.tag) && // not a built-in
       isPlatformReservedTag(node.tag) && // not a component
       !isDirectChildOfTemplateFor(node) &&
       Object.keys(node).every(isStaticKey)
     ))
   }
 
   function isDirectChildOfTemplateFor (node) {
     while (node.parent) {
       node = node.parent;
       if (node.tag !== 'template') {
         return false
       }
       if (node.for) {
         return true
       }
     }
     return false
   }
 
   /*  */
 
   var fnExpRE = /^([\w$_]+|\([^)]*?\))\s*=>|^function(?:\s+[\w$]+)?\s*\(/;
   var fnInvokeRE = /\([^)]*?\);*$/;
   var simplePathRE = /^[A-Za-z_$][\w$]*(?:\.[A-Za-z_$][\w$]*|\['[^']*?']|\["[^"]*?"]|\[\d+]|\[[A-Za-z_$][\w$]*])*$/;
 
   // KeyboardEvent.keyCode aliases
   var keyCodes = {
     esc: 27,
     tab: 9,
     enter: 13,
     space: 32,
     up: 38,
     left: 37,
     right: 39,
     down: 40,
     'delete': [8, 46]
   };
 
   // KeyboardEvent.key aliases
   var keyNames = {
     // #7880: IE11 and Edge use `Esc` for Escape key name.
     esc: ['Esc', 'Escape'],
     tab: 'Tab',
     enter: 'Enter',
     // #9112: IE11 uses `Spacebar` for Space key name.
     space: [' ', 'Spacebar'],
     // #7806: IE11 uses key names without `Arrow` prefix for arrow keys.
     up: ['Up', 'ArrowUp'],
     left: ['Left', 'ArrowLeft'],
     right: ['Right', 'ArrowRight'],
     down: ['Down', 'ArrowDown'],
     // #9112: IE11 uses `Del` for Delete key name.
     'delete': ['Backspace', 'Delete', 'Del']
   };
 
   // #4868: modifiers that prevent the execution of the listener
   // need to explicitly return null so that we can determine whether to remove
   // the listener for .once
   var genGuard = function (condition) { return ("if(" + condition + ")return null;"); };
 
   var modifierCode = {
     stop: '$event.stopPropagation();',
     prevent: '$event.preventDefault();',
     self: genGuard("$event.target !== $event.currentTarget"),
     ctrl: genGuard("!$event.ctrlKey"),
     shift: genGuard("!$event.shiftKey"),
     alt: genGuard("!$event.altKey"),
     meta: genGuard("!$event.metaKey"),
     left: genGuard("'button' in $event && $event.button !== 0"),
     middle: genGuard("'button' in $event && $event.button !== 1"),
     right: genGuard("'button' in $event && $event.button !== 2")
   };
 
   function genHandlers (
     events,
     isNative
   ) {
     var prefix = isNative ? 'nativeOn:' : 'on:';
     var staticHandlers = "";
     var dynamicHandlers = "";
     for (var name in events) {
       var handlerCode = genHandler(events[name]);
       if (events[name] && events[name].dynamic) {
         dynamicHandlers += name + "," + handlerCode + ",";
       } else {
         staticHandlers += "\"" + name + "\":" + handlerCode + ",";
       }
     }
     staticHandlers = "{" + (staticHandlers.slice(0, -1)) + "}";
     if (dynamicHandlers) {
       return prefix + "_d(" + staticHandlers + ",[" + (dynamicHandlers.slice(0, -1)) + "])"
     } else {
       return prefix + staticHandlers
     }
   }
 
   function genHandler (handler) {
     if (!handler) {
       return 'function(){}'
     }
 
     if (Array.isArray(handler)) {
       return ("[" + (handler.map(function (handler) { return genHandler(handler); }).join(',')) + "]")
     }
 
     var isMethodPath = simplePathRE.test(handler.value);
     var isFunctionExpression = fnExpRE.test(handler.value);
     var isFunctionInvocation = simplePathRE.test(handler.value.replace(fnInvokeRE, ''));
 
     if (!handler.modifiers) {
       if (isMethodPath || isFunctionExpression) {
         return handler.value
       }
       return ("function($event){" + (isFunctionInvocation ? ("return " + (handler.value)) : handler.value) + "}") // inline statement
     } else {
       var code = '';
       var genModifierCode = '';
       var keys = [];
       for (var key in handler.modifiers) {
         if (modifierCode[key]) {
           genModifierCode += modifierCode[key];
           // left/right
           if (keyCodes[key]) {
             keys.push(key);
           }
         } else if (key === 'exact') {
           var modifiers = (handler.modifiers);
           genModifierCode += genGuard(
             ['ctrl', 'shift', 'alt', 'meta']
               .filter(function (keyModifier) { return !modifiers[keyModifier]; })
               .map(function (keyModifier) { return ("$event." + keyModifier + "Key"); })
               .join('||')
           );
         } else {
           keys.push(key);
         }
       }
       if (keys.length) {
         code += genKeyFilter(keys);
       }
       // Make sure modifiers like prevent and stop get executed after key filtering
       if (genModifierCode) {
         code += genModifierCode;
       }
       var handlerCode = isMethodPath
         ? ("return " + (handler.value) + "($event)")
         : isFunctionExpression
           ? ("return (" + (handler.value) + ")($event)")
           : isFunctionInvocation
             ? ("return " + (handler.value))
             : handler.value;
       return ("function($event){" + code + handlerCode + "}")
     }
   }
 
   function genKeyFilter (keys) {
     return (
       // make sure the key filters only apply to KeyboardEvents
       // #9441: can't use 'keyCode' in $event because Chrome autofill fires fake
       // key events that do not have keyCode property...
       "if(!$event.type.indexOf('key')&&" +
       (keys.map(genFilterCode).join('&&')) + ")return null;"
     )
   }
 
   function genFilterCode (key) {
     var keyVal = parseInt(key, 10);
     if (keyVal) {
       return ("$event.keyCode!==" + keyVal)
     }
     var keyCode = keyCodes[key];
     var keyName = keyNames[key];
     return (
       "_k($event.keyCode," +
       (JSON.stringify(key)) + "," +
       (JSON.stringify(keyCode)) + "," +
       "$event.key," +
       "" + (JSON.stringify(keyName)) +
       ")"
     )
   }
 
   /*  */
 
   function on (el, dir) {
     if (dir.modifiers) {
       warn("v-on without argument does not support modifiers.");
     }
     el.wrapListeners = function (code) { return ("_g(" + code + "," + (dir.value) + ")"); };
   }
 
   /*  */
 
   function bind$1 (el, dir) {
     el.wrapData = function (code) {
       return ("_b(" + code + ",'" + (el.tag) + "'," + (dir.value) + "," + (dir.modifiers && dir.modifiers.prop ? 'true' : 'false') + (dir.modifiers && dir.modifiers.sync ? ',true' : '') + ")")
     };
   }
 
   /*  */
 
   var baseDirectives = {
     on: on,
     bind: bind$1,
     cloak: noop
   };
 
   /*  */
 
 
 
 
 
   var CodegenState = function CodegenState (options) {
     this.options = options;
     this.warn = options.warn || baseWarn;
     this.transforms = pluckModuleFunction(options.modules, 'transformCode');
     this.dataGenFns = pluckModuleFunction(options.modules, 'genData');
     this.directives = extend(extend({}, baseDirectives), options.directives);
     var isReservedTag = options.isReservedTag || no;
     this.maybeComponent = function (el) { return !!el.component || !isReservedTag(el.tag); };
     this.onceId = 0;
     this.staticRenderFns = [];
     this.pre = false;
   };
 
 
 
   function generate (
     ast,
     options
   ) {
     var state = new CodegenState(options);
     var code = ast ? genElement(ast, state) : '_c("div")';
     return {
       render: ("with(this){return " + code + "}"),
       staticRenderFns: state.staticRenderFns
     }
   }
 
   function genElement (el, state) {
     if (el.parent) {
       el.pre = el.pre || el.parent.pre;
     }
 
     if (el.staticRoot && !el.staticProcessed) {
       return genStatic(el, state)
     } else if (el.once && !el.onceProcessed) {
       return genOnce(el, state)
     } else if (el.for && !el.forProcessed) {
       return genFor(el, state)
     } else if (el.if && !el.ifProcessed) {
       return genIf(el, state)
     } else if (el.tag === 'template' && !el.slotTarget && !state.pre) {
       return genChildren(el, state) || 'void 0'
     } else if (el.tag === 'slot') {
       return genSlot(el, state)
     } else {
       // component or element
       var code;
       if (el.component) {
         code = genComponent(el.component, el, state);
       } else {
         var data;
         if (!el.plain || (el.pre && state.maybeComponent(el))) {
           data = genData$2(el, state);
         }
 
         var children = el.inlineTemplate ? null : genChildren(el, state, true);
         code = "_c('" + (el.tag) + "'" + (data ? ("," + data) : '') + (children ? ("," + children) : '') + ")";
       }
       // module transforms
       for (var i = 0; i < state.transforms.length; i++) {
         code = state.transforms[i](el, code);
       }
       return code
     }
   }
 
   // hoist static sub-trees out
   function genStatic (el, state) {
     el.staticProcessed = true;
     // Some elements (templates) need to behave differently inside of a v-pre
     // node.  All pre nodes are static roots, so we can use this as a location to
     // wrap a state change and reset it upon exiting the pre node.
     var originalPreState = state.pre;
     if (el.pre) {
       state.pre = el.pre;
     }
     state.staticRenderFns.push(("with(this){return " + (genElement(el, state)) + "}"));
     state.pre = originalPreState;
     return ("_m(" + (state.staticRenderFns.length - 1) + (el.staticInFor ? ',true' : '') + ")")
   }
 
   // v-once
   function genOnce (el, state) {
     el.onceProcessed = true;
     if (el.if && !el.ifProcessed) {
       return genIf(el, state)
     } else if (el.staticInFor) {
       var key = '';
       var parent = el.parent;
       while (parent) {
         if (parent.for) {
           key = parent.key;
           break
         }
         parent = parent.parent;
       }
       if (!key) {
         state.warn(
           "v-once can only be used inside v-for that is keyed. ",
           el.rawAttrsMap['v-once']
         );
         return genElement(el, state)
       }
       return ("_o(" + (genElement(el, state)) + "," + (state.onceId++) + "," + key + ")")
     } else {
       return genStatic(el, state)
     }
   }
 
   function genIf (
     el,
     state,
     altGen,
     altEmpty
   ) {
     el.ifProcessed = true; // avoid recursion
     return genIfConditions(el.ifConditions.slice(), state, altGen, altEmpty)
   }
 
   function genIfConditions (
     conditions,
     state,
     altGen,
     altEmpty
   ) {
     if (!conditions.length) {
       return altEmpty || '_e()'
     }
 
     var condition = conditions.shift();
     if (condition.exp) {
       return ("(" + (condition.exp) + ")?" + (genTernaryExp(condition.block)) + ":" + (genIfConditions(conditions, state, altGen, altEmpty)))
     } else {
       return ("" + (genTernaryExp(condition.block)))
     }
 
     // v-if with v-once should generate code like (a)?_m(0):_m(1)
     function genTernaryExp (el) {
       return altGen
         ? altGen(el, state)
         : el.once
           ? genOnce(el, state)
           : genElement(el, state)
     }
   }
 
   function genFor (
     el,
     state,
     altGen,
     altHelper
   ) {
     var exp = el.for;
     var alias = el.alias;
     var iterator1 = el.iterator1 ? ("," + (el.iterator1)) : '';
     var iterator2 = el.iterator2 ? ("," + (el.iterator2)) : '';
 
     if (state.maybeComponent(el) &&
       el.tag !== 'slot' &&
       el.tag !== 'template' &&
       !el.key
     ) {
       state.warn(
         "<" + (el.tag) + " v-for=\"" + alias + " in " + exp + "\">: component lists rendered with " +
         "v-for should have explicit keys. " +
         "See https://vuejs.org/guide/list.html#key for more info.",
         el.rawAttrsMap['v-for'],
         true /* tip */
       );
     }
 
     el.forProcessed = true; // avoid recursion
     return (altHelper || '_l') + "((" + exp + ")," +
       "function(" + alias + iterator1 + iterator2 + "){" +
         "return " + ((altGen || genElement)(el, state)) +
       '})'
   }
 
   function genData$2 (el, state) {
     var data = '{';
 
     // directives first.
     // directives may mutate the el's other properties before they are generated.
     var dirs = genDirectives(el, state);
     if (dirs) { data += dirs + ','; }
 
     // key
     if (el.key) {
       data += "key:" + (el.key) + ",";
     }
     // ref
     if (el.ref) {
       data += "ref:" + (el.ref) + ",";
     }
     if (el.refInFor) {
       data += "refInFor:true,";
     }
     // pre
     if (el.pre) {
       data += "pre:true,";
     }
     // record original tag name for components using "is" attribute
     if (el.component) {
       data += "tag:\"" + (el.tag) + "\",";
     }
     // module data generation functions
     for (var i = 0; i < state.dataGenFns.length; i++) {
       data += state.dataGenFns[i](el);
     }
     // attributes
     if (el.attrs) {
       data += "attrs:" + (genProps(el.attrs)) + ",";
     }
     // DOM props
     if (el.props) {
       data += "domProps:" + (genProps(el.props)) + ",";
     }
     // event handlers
     if (el.events) {
       data += (genHandlers(el.events, false)) + ",";
     }
     if (el.nativeEvents) {
       data += (genHandlers(el.nativeEvents, true)) + ",";
     }
     // slot target
     // only for non-scoped slots
     if (el.slotTarget && !el.slotScope) {
       data += "slot:" + (el.slotTarget) + ",";
     }
     // scoped slots
     if (el.scopedSlots) {
       data += (genScopedSlots(el, el.scopedSlots, state)) + ",";
     }
     // component v-model
     if (el.model) {
       data += "model:{value:" + (el.model.value) + ",callback:" + (el.model.callback) + ",expression:" + (el.model.expression) + "},";
     }
     // inline-template
     if (el.inlineTemplate) {
       var inlineTemplate = genInlineTemplate(el, state);
       if (inlineTemplate) {
         data += inlineTemplate + ",";
       }
     }
     data = data.replace(/,$/, '') + '}';
     // v-bind dynamic argument wrap
     // v-bind with dynamic arguments must be applied using the same v-bind object
     // merge helper so that class/style/mustUseProp attrs are handled correctly.
     if (el.dynamicAttrs) {
       data = "_b(" + data + ",\"" + (el.tag) + "\"," + (genProps(el.dynamicAttrs)) + ")";
     }
     // v-bind data wrap
     if (el.wrapData) {
       data = el.wrapData(data);
     }
     // v-on data wrap
     if (el.wrapListeners) {
       data = el.wrapListeners(data);
     }
     return data
   }
 
   function genDirectives (el, state) {
     var dirs = el.directives;
     if (!dirs) { return }
     var res = 'directives:[';
     var hasRuntime = false;
     var i, l, dir, needRuntime;
     for (i = 0, l = dirs.length; i < l; i++) {
       dir = dirs[i];
       needRuntime = true;
       var gen = state.directives[dir.name];
       if (gen) {
         // compile-time directive that manipulates AST.
         // returns true if it also needs a runtime counterpart.
         needRuntime = !!gen(el, dir, state.warn);
       }
       if (needRuntime) {
         hasRuntime = true;
         res += "{name:\"" + (dir.name) + "\",rawName:\"" + (dir.rawName) + "\"" + (dir.value ? (",value:(" + (dir.value) + "),expression:" + (JSON.stringify(dir.value))) : '') + (dir.arg ? (",arg:" + (dir.isDynamicArg ? dir.arg : ("\"" + (dir.arg) + "\""))) : '') + (dir.modifiers ? (",modifiers:" + (JSON.stringify(dir.modifiers))) : '') + "},";
       }
     }
     if (hasRuntime) {
       return res.slice(0, -1) + ']'
     }
   }
 
   function genInlineTemplate (el, state) {
     var ast = el.children[0];
     if (el.children.length !== 1 || ast.type !== 1) {
       state.warn(
         'Inline-template components must have exactly one child element.',
         { start: el.start }
       );
     }
     if (ast && ast.type === 1) {
       var inlineRenderFns = generate(ast, state.options);
       return ("inlineTemplate:{render:function(){" + (inlineRenderFns.render) + "},staticRenderFns:[" + (inlineRenderFns.staticRenderFns.map(function (code) { return ("function(){" + code + "}"); }).join(',')) + "]}")
     }
   }
 
   function genScopedSlots (
     el,
     slots,
     state
   ) {
     // by default scoped slots are considered "stable", this allows child
     // components with only scoped slots to skip forced updates from parent.
     // but in some cases we have to bail-out of this optimization
     // for example if the slot contains dynamic names, has v-if or v-for on them...
     var needsForceUpdate = el.for || Object.keys(slots).some(function (key) {
       var slot = slots[key];
       return (
         slot.slotTargetDynamic ||
         slot.if ||
         slot.for ||
         containsSlotChild(slot) // is passing down slot from parent which may be dynamic
       )
     });
 
     // #9534: if a component with scoped slots is inside a conditional branch,
     // it's possible for the same component to be reused but with different
     // compiled slot content. To avoid that, we generate a unique key based on
     // the generated code of all the slot contents.
     var needsKey = !!el.if;
 
     // OR when it is inside another scoped slot or v-for (the reactivity may be
     // disconnected due to the intermediate scope variable)
     // #9438, #9506
     // TODO: this can be further optimized by properly analyzing in-scope bindings
     // and skip force updating ones that do not actually use scope variables.
     if (!needsForceUpdate) {
       var parent = el.parent;
       while (parent) {
         if (
           (parent.slotScope && parent.slotScope !== emptySlotScopeToken) ||
           parent.for
         ) {
           needsForceUpdate = true;
           break
         }
         if (parent.if) {
           needsKey = true;
         }
         parent = parent.parent;
       }
     }
 
     var generatedSlots = Object.keys(slots)
       .map(function (key) { return genScopedSlot(slots[key], state); })
       .join(',');
 
     return ("scopedSlots:_u([" + generatedSlots + "]" + (needsForceUpdate ? ",null,true" : "") + (!needsForceUpdate && needsKey ? (",null,false," + (hash(generatedSlots))) : "") + ")")
   }
 
   function hash(str) {
     var hash = 5381;
     var i = str.length;
     while(i) {
       hash = (hash * 33) ^ str.charCodeAt(--i);
     }
     return hash >>> 0
   }
 
   function containsSlotChild (el) {
     if (el.type === 1) {
       if (el.tag === 'slot') {
         return true
       }
       return el.children.some(containsSlotChild)
     }
     return false
   }
 
   function genScopedSlot (
     el,
     state
   ) {
     var isLegacySyntax = el.attrsMap['slot-scope'];
     if (el.if && !el.ifProcessed && !isLegacySyntax) {
       return genIf(el, state, genScopedSlot, "null")
     }
     if (el.for && !el.forProcessed) {
       return genFor(el, state, genScopedSlot)
     }
     var slotScope = el.slotScope === emptySlotScopeToken
       ? ""
       : String(el.slotScope);
     var fn = "function(" + slotScope + "){" +
       "return " + (el.tag === 'template'
         ? el.if && isLegacySyntax
           ? ("(" + (el.if) + ")?" + (genChildren(el, state) || 'undefined') + ":undefined")
           : genChildren(el, state) || 'undefined'
         : genElement(el, state)) + "}";
     // reverse proxy v-slot without scope on this.$slots
     var reverseProxy = slotScope ? "" : ",proxy:true";
     return ("{key:" + (el.slotTarget || "\"default\"") + ",fn:" + fn + reverseProxy + "}")
   }
 
   function genChildren (
     el,
     state,
     checkSkip,
     altGenElement,
     altGenNode
   ) {
     var children = el.children;
     if (children.length) {
       var el$1 = children[0];
       // optimize single v-for
       if (children.length === 1 &&
         el$1.for &&
         el$1.tag !== 'template' &&
         el$1.tag !== 'slot'
       ) {
         var normalizationType = checkSkip
           ? state.maybeComponent(el$1) ? ",1" : ",0"
           : "";
         return ("" + ((altGenElement || genElement)(el$1, state)) + normalizationType)
       }
       var normalizationType$1 = checkSkip
         ? getNormalizationType(children, state.maybeComponent)
         : 0;
       var gen = altGenNode || genNode;
       return ("[" + (children.map(function (c) { return gen(c, state); }).join(',')) + "]" + (normalizationType$1 ? ("," + normalizationType$1) : ''))
     }
   }
 
   // determine the normalization needed for the children array.
   // 0: no normalization needed
   // 1: simple normalization needed (possible 1-level deep nested array)
   // 2: full normalization needed
   function getNormalizationType (
     children,
     maybeComponent
   ) {
     var res = 0;
     for (var i = 0; i < children.length; i++) {
       var el = children[i];
       if (el.type !== 1) {
         continue
       }
       if (needsNormalization(el) ||
           (el.ifConditions && el.ifConditions.some(function (c) { return needsNormalization(c.block); }))) {
         res = 2;
         break
       }
       if (maybeComponent(el) ||
           (el.ifConditions && el.ifConditions.some(function (c) { return maybeComponent(c.block); }))) {
         res = 1;
       }
     }
     return res
   }
 
   function needsNormalization (el) {
     return el.for !== undefined || el.tag === 'template' || el.tag === 'slot'
   }
 
   function genNode (node, state) {
     if (node.type === 1) {
       return genElement(node, state)
     } else if (node.type === 3 && node.isComment) {
       return genComment(node)
     } else {
       return genText(node)
     }
   }
 
   function genText (text) {
     return ("_v(" + (text.type === 2
       ? text.expression // no need for () because already wrapped in _s()
       : transformSpecialNewlines(JSON.stringify(text.text))) + ")")
   }
 
   function genComment (comment) {
     return ("_e(" + (JSON.stringify(comment.text)) + ")")
   }
 
   function genSlot (el, state) {
     var slotName = el.slotName || '"default"';
     var children = genChildren(el, state);
     var res = "_t(" + slotName + (children ? ("," + children) : '');
     var attrs = el.attrs || el.dynamicAttrs
       ? genProps((el.attrs || []).concat(el.dynamicAttrs || []).map(function (attr) { return ({
           // slot props are camelized
           name: camelize(attr.name),
           value: attr.value,
           dynamic: attr.dynamic
         }); }))
       : null;
     var bind$$1 = el.attrsMap['v-bind'];
     if ((attrs || bind$$1) && !children) {
       res += ",null";
     }
     if (attrs) {
       res += "," + attrs;
     }
     if (bind$$1) {
       res += (attrs ? '' : ',null') + "," + bind$$1;
     }
     return res + ')'
   }
 
   // componentName is el.component, take it as argument to shun flow's pessimistic refinement
   function genComponent (
     componentName,
     el,
     state
   ) {
     var children = el.inlineTemplate ? null : genChildren(el, state, true);
     return ("_c(" + componentName + "," + (genData$2(el, state)) + (children ? ("," + children) : '') + ")")
   }
 
   function genProps (props) {
     var staticProps = "";
     var dynamicProps = "";
     for (var i = 0; i < props.length; i++) {
       var prop = props[i];
       var value = transformSpecialNewlines(prop.value);
       if (prop.dynamic) {
         dynamicProps += (prop.name) + "," + value + ",";
       } else {
         staticProps += "\"" + (prop.name) + "\":" + value + ",";
       }
     }
     staticProps = "{" + (staticProps.slice(0, -1)) + "}";
     if (dynamicProps) {
       return ("_d(" + staticProps + ",[" + (dynamicProps.slice(0, -1)) + "])")
     } else {
       return staticProps
     }
   }
 
   // #3895, #4268
   function transformSpecialNewlines (text) {
     return text
       .replace(/\u2028/g, '\\u2028')
       .replace(/\u2029/g, '\\u2029')
   }
 
   /*  */
 
 
 
   // these keywords should not appear inside expressions, but operators like
   // typeof, instanceof and in are allowed
   var prohibitedKeywordRE = new RegExp('\\b' + (
     'do,if,for,let,new,try,var,case,else,with,await,break,catch,class,const,' +
     'super,throw,while,yield,delete,export,import,return,switch,default,' +
     'extends,finally,continue,debugger,function,arguments'
   ).split(',').join('\\b|\\b') + '\\b');
 
   // these unary operators should not be used as property/method names
   var unaryOperatorsRE = new RegExp('\\b' + (
     'delete,typeof,void'
   ).split(',').join('\\s*\\([^\\)]*\\)|\\b') + '\\s*\\([^\\)]*\\)');
 
   // strip strings in expressions
   var stripStringRE = /'(?:[^'\\]|\\.)*'|"(?:[^"\\]|\\.)*"|`(?:[^`\\]|\\.)*\$\{|\}(?:[^`\\]|\\.)*`|`(?:[^`\\]|\\.)*`/g;
 
   // detect problematic expressions in a template
   function detectErrors (ast, warn) {
     if (ast) {
       checkNode(ast, warn);
     }
   }
 
   function checkNode (node, warn) {
     if (node.type === 1) {
       for (var name in node.attrsMap) {
         if (dirRE.test(name)) {
           var value = node.attrsMap[name];
           if (value) {
             var range = node.rawAttrsMap[name];
             if (name === 'v-for') {
               checkFor(node, ("v-for=\"" + value + "\""), warn, range);
             } else if (name === 'v-slot' || name[0] === '#') {
               checkFunctionParameterExpression(value, (name + "=\"" + value + "\""), warn, range);
             } else if (onRE.test(name)) {
               checkEvent(value, (name + "=\"" + value + "\""), warn, range);
             } else {
               checkExpression(value, (name + "=\"" + value + "\""), warn, range);
             }
           }
         }
       }
       if (node.children) {
         for (var i = 0; i < node.children.length; i++) {
           checkNode(node.children[i], warn);
         }
       }
     } else if (node.type === 2) {
       checkExpression(node.expression, node.text, warn, node);
     }
   }
 
   function checkEvent (exp, text, warn, range) {
     var stripped = exp.replace(stripStringRE, '');
     var keywordMatch = stripped.match(unaryOperatorsRE);
     if (keywordMatch && stripped.charAt(keywordMatch.index - 1) !== '$') {
       warn(
         "avoid using JavaScript unary operator as property name: " +
         "\"" + (keywordMatch[0]) + "\" in expression " + (text.trim()),
         range
       );
     }
     checkExpression(exp, text, warn, range);
   }
 
   function checkFor (node, text, warn, range) {
     checkExpression(node.for || '', text, warn, range);
     checkIdentifier(node.alias, 'v-for alias', text, warn, range);
     checkIdentifier(node.iterator1, 'v-for iterator', text, warn, range);
     checkIdentifier(node.iterator2, 'v-for iterator', text, warn, range);
   }
 
   function checkIdentifier (
     ident,
     type,
     text,
     warn,
     range
   ) {
     if (typeof ident === 'string') {
       try {
         new Function(("var " + ident + "=_"));
       } catch (e) {
         warn(("invalid " + type + " \"" + ident + "\" in expression: " + (text.trim())), range);
       }
     }
   }
 
   function checkExpression (exp, text, warn, range) {
     try {
       new Function(("return " + exp));
     } catch (e) {
       var keywordMatch = exp.replace(stripStringRE, '').match(prohibitedKeywordRE);
       if (keywordMatch) {
         warn(
           "avoid using JavaScript keyword as property name: " +
           "\"" + (keywordMatch[0]) + "\"\n  Raw expression: " + (text.trim()),
           range
         );
       } else {
         warn(
           "invalid expression: " + (e.message) + " in\n\n" +
           "    " + exp + "\n\n" +
           "  Raw expression: " + (text.trim()) + "\n",
           range
         );
       }
     }
   }
 
   function checkFunctionParameterExpression (exp, text, warn, range) {
     try {
       new Function(exp, '');
     } catch (e) {
       warn(
         "invalid function parameter expression: " + (e.message) + " in\n\n" +
         "    " + exp + "\n\n" +
         "  Raw expression: " + (text.trim()) + "\n",
         range
       );
     }
   }
 
   /*  */
 
   var range = 2;
 
   function generateCodeFrame (
     source,
     start,
     end
   ) {
     if ( start === void 0 ) start = 0;
     if ( end === void 0 ) end = source.length;
 
     var lines = source.split(/\r?\n/);
     var count = 0;
     var res = [];
     for (var i = 0; i < lines.length; i++) {
       count += lines[i].length + 1;
       if (count >= start) {
         for (var j = i - range; j <= i + range || end > count; j++) {
           if (j < 0 || j >= lines.length) { continue }
           res.push(("" + (j + 1) + (repeat$1(" ", 3 - String(j + 1).length)) + "|  " + (lines[j])));
           var lineLength = lines[j].length;
           if (j === i) {
             // push underline
             var pad = start - (count - lineLength) + 1;
             var length = end > count ? lineLength - pad : end - start;
             res.push("   |  " + repeat$1(" ", pad) + repeat$1("^", length));
           } else if (j > i) {
             if (end > count) {
               var length$1 = Math.min(end - count, lineLength);
               res.push("   |  " + repeat$1("^", length$1));
             }
             count += lineLength + 1;
           }
         }
         break
       }
     }
     return res.join('\n')
   }
 
   function repeat$1 (str, n) {
     var result = '';
     if (n > 0) {
       while (true) { // eslint-disable-line
         if (n & 1) { result += str; }
         n >>>= 1;
         if (n <= 0) { break }
         str += str;
       }
     }
     return result
   }
 
   /*  */
 
 
 
   function createFunction (code, errors) {
     try {
       return new Function(code)
     } catch (err) {
       errors.push({ err: err, code: code });
       return noop
     }
   }
 
   function createCompileToFunctionFn (compile) {
     var cache = Object.create(null);
 
     return function compileToFunctions (
       template,
       options,
       vm
     ) {
       options = extend({}, options);
       var warn$$1 = options.warn || warn;
       delete options.warn;
 
       /* istanbul ignore if */
       {
         // detect possible CSP restriction
         try {
           new Function('return 1');
         } catch (e) {
           if (e.toString().match(/unsafe-eval|CSP/)) {
             warn$$1(
               'It seems you are using the standalone build of Vue.js in an ' +
               'environment with Content Security Policy that prohibits unsafe-eval. ' +
               'The template compiler cannot work in this environment. Consider ' +
               'relaxing the policy to allow unsafe-eval or pre-compiling your ' +
               'templates into render functions.'
             );
           }
         }
       }
 
       // check cache
       var key = options.delimiters
         ? String(options.delimiters) + template
         : template;
       if (cache[key]) {
         return cache[key]
       }
 
       // compile
       var compiled = compile(template, options);
 
       // check compilation errors/tips
       {
         if (compiled.errors && compiled.errors.length) {
           if (options.outputSourceRange) {
             compiled.errors.forEach(function (e) {
               warn$$1(
                 "Error compiling template:\n\n" + (e.msg) + "\n\n" +
                 generateCodeFrame(template, e.start, e.end),
                 vm
               );
             });
           } else {
             warn$$1(
               "Error compiling template:\n\n" + template + "\n\n" +
               compiled.errors.map(function (e) { return ("- " + e); }).join('\n') + '\n',
               vm
             );
           }
         }
         if (compiled.tips && compiled.tips.length) {
           if (options.outputSourceRange) {
             compiled.tips.forEach(function (e) { return tip(e.msg, vm); });
           } else {
             compiled.tips.forEach(function (msg) { return tip(msg, vm); });
           }
         }
       }
 
       // turn code into functions
       var res = {};
       var fnGenErrors = [];
       res.render = createFunction(compiled.render, fnGenErrors);
       res.staticRenderFns = compiled.staticRenderFns.map(function (code) {
         return createFunction(code, fnGenErrors)
       });
 
       // check function generation errors.
       // this should only happen if there is a bug in the compiler itself.
       // mostly for codegen development use
       /* istanbul ignore if */
       {
         if ((!compiled.errors || !compiled.errors.length) && fnGenErrors.length) {
           warn$$1(
             "Failed to generate render function:\n\n" +
             fnGenErrors.map(function (ref) {
               var err = ref.err;
               var code = ref.code;
 
               return ((err.toString()) + " in\n\n" + code + "\n");
           }).join('\n'),
             vm
           );
         }
       }
 
       return (cache[key] = res)
     }
   }
 
   /*  */
 
   function createCompilerCreator (baseCompile) {
     return function createCompiler (baseOptions) {
       function compile (
         template,
         options
       ) {
         var finalOptions = Object.create(baseOptions);
         var errors = [];
         var tips = [];
 
         var warn = function (msg, range, tip) {
           (tip ? tips : errors).push(msg);
         };
 
         if (options) {
           if (options.outputSourceRange) {
             // $flow-disable-line
             var leadingSpaceLength = template.match(/^\s*/)[0].length;
 
             warn = function (msg, range, tip) {
               var data = { msg: msg };
               if (range) {
                 if (range.start != null) {
                   data.start = range.start + leadingSpaceLength;
                 }
                 if (range.end != null) {
                   data.end = range.end + leadingSpaceLength;
                 }
               }
               (tip ? tips : errors).push(data);
             };
           }
           // merge custom modules
           if (options.modules) {
             finalOptions.modules =
               (baseOptions.modules || []).concat(options.modules);
           }
           // merge custom directives
           if (options.directives) {
             finalOptions.directives = extend(
               Object.create(baseOptions.directives || null),
               options.directives
             );
           }
           // copy other options
           for (var key in options) {
             if (key !== 'modules' && key !== 'directives') {
               finalOptions[key] = options[key];
             }
           }
         }
 
         finalOptions.warn = warn;
 
         var compiled = baseCompile(template.trim(), finalOptions);
         {
           detectErrors(compiled.ast, warn);
         }
         compiled.errors = errors;
         compiled.tips = tips;
         return compiled
       }
 
       return {
         compile: compile,
         compileToFunctions: createCompileToFunctionFn(compile)
       }
     }
   }
 
   /*  */
 
   // `createCompilerCreator` allows creating compilers that use alternative
   // parser/optimizer/codegen, e.g the SSR optimizing compiler.
   // Here we just export a default compiler using the default parts.
   var createCompiler = createCompilerCreator(function baseCompile (
     template,
     options
   ) {
     var ast = parse(template.trim(), options);
     if (options.optimize !== false) {
       optimize(ast, options);
     }
     var code = generate(ast, options);
     return {
       ast: ast,
       render: code.render,
       staticRenderFns: code.staticRenderFns
     }
   });
 
   /*  */
 
   var ref$1 = createCompiler(baseOptions);
   var compile = ref$1.compile;
   var compileToFunctions = ref$1.compileToFunctions;
 
   /*  */
 
   // check whether current browser encodes a char inside attribute values
   var div;
   function getShouldDecode (href) {
     div = div || document.createElement('div');
     div.innerHTML = href ? "<a href=\"\n\"/>" : "<div a=\"\n\"/>";
     return div.innerHTML.indexOf('&#10;') > 0
   }
 
   // #3663: IE encodes newlines inside attribute values while other browsers don't
   var shouldDecodeNewlines = inBrowser ? getShouldDecode(false) : false;
   // #6828: chrome encodes content in a[href]
   var shouldDecodeNewlinesForHref = inBrowser ? getShouldDecode(true) : false;
 
   /*  */
 
   var idToTemplate = cached(function (id) {
     var el = query(id);
     return el && el.innerHTML
   });
 
   var mount = Vue.prototype.$mount;
   Vue.prototype.$mount = function (
     el,
     hydrating
   ) {
     el = el && query(el);
 
     /* istanbul ignore if */
     if (el === document.body || el === document.documentElement) {
       warn(
         "Do not mount Vue to <html> or <body> - mount to normal elements instead."
       );
       return this
     }
 
     var options = this.$options;
     // resolve template/el and convert to render function
     if (!options.render) {
       var template = options.template;
       if (template) {
         if (typeof template === 'string') {
           if (template.charAt(0) === '#') {
             template = idToTemplate(template);
             /* istanbul ignore if */
             if (!template) {
               warn(
                 ("Template element not found or is empty: " + (options.template)),
                 this
               );
             }
           }
         } else if (template.nodeType) {
           template = template.innerHTML;
         } else {
           {
             warn('invalid template option:' + template, this);
           }
           return this
         }
       } else if (el) {
         template = getOuterHTML(el);
       }
       if (template) {
         /* istanbul ignore if */
         if (config.performance && mark) {
           mark('compile');
         }
 
         var ref = compileToFunctions(template, {
           outputSourceRange: "development" !== 'production',
           shouldDecodeNewlines: shouldDecodeNewlines,
           shouldDecodeNewlinesForHref: shouldDecodeNewlinesForHref,
           delimiters: options.delimiters,
           comments: options.comments
         }, this);
         var render = ref.render;
         var staticRenderFns = ref.staticRenderFns;
         options.render = render;
         options.staticRenderFns = staticRenderFns;
 
         /* istanbul ignore if */
         if (config.performance && mark) {
           mark('compile end');
           measure(("vue " + (this._name) + " compile"), 'compile', 'compile end');
         }
       }
     }
     return mount.call(this, el, hydrating)
   };
 
   /**
    * Get outerHTML of elements, taking care
    * of SVG elements in IE as well.
    */
   function getOuterHTML (el) {
     if (el.outerHTML) {
       return el.outerHTML
     } else {
       var container = document.createElement('div');
       container.appendChild(el.cloneNode(true));
       return container.innerHTML
     }
   }
 
   Vue.compile = compileToFunctions;
 
   return Vue;
 
 }));
 